Okay, I am going on memory (as a Menzerna user, I often get confused)…
Menzerna is primarily (and MenzernaUSA was primarily) an OEM/body shop company. At the OEM level a different set of standards has to be met (in addition to the particular requirements that we, the enthusiasts, detailers, and end-users look for: clarity, finish, performance). At the OEM level it gets a little more particular (although our standards for finish are generally higher) because factors like paint type, speed, dust, chemical use, etc have to be factored in.
For example Menzerna offers both 106ff and 106fa, and much like the names suggest, the products are very similar. If memory serves me correctly, the only difference is that fa features a slight tweak to the lubrication to hold the abrasive against the pad. This is to slightly decrease the working time (making the product ‘faster’) to meet the specific requirements of one particular BMW shop that works at a slightly faster speed (more cars per minute=less time to polish them).
Now when we take this ‘tweak’ into the enthusiast or detailer market (we are no longer polishing fresh paint, we are removing different defects, and possibly most important we are polishing in a dynamic environment with various machines) this ‘tweak’ may lead other results that wouldn’t show up at the OEM level. Often times we know more about using their products in our environment because our standards (for finishing) are often higher and because we are using their products ‘incorrectly’.
Remember, when properautocare/cma first brought Menzerna to the US for the enthusiast market (2002ish?) they had to directly purchase the product from Germany (hence the different labels even today) because the distributor in America had no interest in the enthusiasts market. These products simply where not designed for this market. CMA had two choices for a middle polish, PO91e (which would become Intensive Polish) and PO85rd3.02 (which would become PO83/PO83q aka Super Intensive Polish, not to be confused with the different PO85rd or PO85 u). When used in the enthusiast market, Super Intensive Polish can have ‘weird’ reactions with particular paint systems, that would go unnoticed at the OEM level (where the product is used and was designed to be used on the same fresh paint, in the same humidity, at the same speed, with the same pad, at the same temperature, and remove the same defects).
Since PO91e (IP) works on all paint types and doesn’t have bad reactions (very consistent) it made it an easy choice if only one could be made. As Menzerna gained popularity in the enthusiast market, more and more products became available or where imported to supplement the line. One of the downsides of this ‘gold rush’ is that E-retailers always try to have the one up on each other, and with so many different products available (given the various tweaks for each specific shop), it didn’t take long for the market place to become flooded and the market to become confused.
So now we have a potential of five selections of finishing polishes, instead of one.

O106ff, PO106fa,PO85u,PO85rd,PO87mc. Remember at the OEM level this makes sense as various tweaks have to be made for certain specifications. In the end user market this leads to a lot of confusion. Couple this in with the fact that we all detail in different environments, on different paints, with different techniques on different machines, and many enthusiasts have many different opinions on works best and the results that have. If you happened to own a factory and needed a specific polish for a specific purpose, there is no company better then Menzerna to formulate the product. Nobody makes a more focused product. However the more focused the product, the narrower that focal scope, and the more problems that can occur.
PO85u
At the OEM level: I believe this is an older, one step finishing polish with a Menzerna rated cut of 3.0 and a gloss of 4.0.
My experience: This product has a fair amount of cut and finishes out nice on all but the softest clears (it might leave light hologramming on real soft paint). It cuts over time and requires a very long work time to break the product down all of the way. Use VERY little product, and medium pressure at first (on a rotary). Personally I think 106ff is much improved version for what we do, working faster, cutting more, and easier to remove.
PO85rd
At the OEM level: I’m not really sure although I believe that 106ff universally replaced PO85rd in Europe as the main refinishing polish.
At the End User Level: Most enthusiasts and detailer prefer 85rd over 106ff for finishing on a rotary polisher. At this level 106ff has show some ability to ‘fill’ defects on particular paints, which is obviously not a problem when it is used at the OEM level as it was designed. Many enthusiasts believe they get a finer, sharper finish with this polish, with more gloss, then any other polish available.
My experience: 85rd is one of the finest polishes I have used, and seems to work well on 95% of the paint’s I have used it on. I find that is one of the only polishes I can use to finish out ultra soft paint perfect on a rotary.
PO87mc (final polish II/micropolish)
At the OEM level: I finishing polish used to remove extremely light marring and increase the gloss of the fresh paint
My experience: 87mc is one of the polishes that introduced the end-user to this line (Final Polish II). For all intensive purposes I tend to find that PO85rd and 87mc leave very similar finishes (extremely fine), have similar working times, and seem almost the same. The oils are easier to remove after polishing (not as stubborn as 85rd). Can be hard to get the ‘perfect shine’ on ultra soft paints (Infiniti G35)
PO106ff
At the OEM Level: Features the finest abrasives (per Menzerna) of any polish they make. Used for finishing cermaclear paints at the OEM level for Mercedes Benz, Maybach, and Rolls-Royce. Replaced 85rd in Europe plants...
At the End User Level: Leaves an amazing gloss, but problems with it leaving holograms and filling very soft paints, have regulated the once highly regarded finishing polish to more a light polishing, final prep step.
My experience: I love 106ff for prepping the paint for a final step with a LC white pad or finishing with a gray pad on harder paints. Work 106ff long with a no cut pad and most fears of long term filling are eliminated.
PO106fA
At the OEM Level: Slight tweak on the popular 106ff polish
At the End User Level: Some people like it more, some people like it less, some people cannot tell a difference. I have heard that it is slightly easier to use on paint’s that do not react well with 106ff.
My experience: Limited, and I cannot tell any functional or visible different (in finish) from 106ff.
Middle Polishes.
PO91e (IP)
OEM Level: Standard finishing polish popular in the body shop market.
At the End User Level: The original Menzerna polish, IP features ultra refined abrasives that level paint with no potential for filling. IP has seemed to decline in popularity because of SIP.
My experience: I like IP a lot. It works on all paints, and provides consistent results. It has a higher dusting factor (jettisoning factor) that helps clean the pad/polish/paint surface when working on contaminated, faded, oxidized, or single stage paints. I have never found IP to show anything but a true factor.
PO83q/PO83/PO85rd3.02 (SIP)
OEM Level: Used by many factories for moderate to severe defect removal, features a very thick lubricant to hold the abrasives in solution to work against harder, high solid paints.
At the End User Level: When it works, it is amazing, with the ability to remove moderate to severe swirl marks and leave a near LSP ready finish on most paint systems. A much focused OEM polish, SIP can have issues when used on particular paints or in particular environments. When
My experience: I have a love-hate relationship with SIP. When it works, it is simply amazing. When it doesn’t work, it can cause buffer hop, spit, sling, dusting, super heating, filling, or anything else. Also seems very sensitive to previous products used on the paint. I always wipe the paint down with alcohol before polishing (to remove any previous chemicals) and after (to inspect for the occasional filling that can occur with the stubborn oils). However, it has such a broad range (from initial cut to final finish) that it usually the first polish out of my bag. I am willing to put up with its short comings because of the great results it has on most paints.