Kelly,
Long post, but bear with me. I want to provide you as much info as I can which I hope will help.
How old is your car, and what condition is the paint in? I would say those are some questions you might want to examine before AIO. I think many here would agree that the "prep" work you do before AIO and SG will make all the difference in the world.
TO answer your question:
AIO will remove the wax and previous SG layers. Here is the "catch 22". AIO does put a light coat of sealant on the car. So, if anything is on your paint underneath the AIO it is "locked in" by the AIO. THen you layer on SG, and you still may have some "things" underneath the AIO and all the SG. So your sitting there, looking at that fresh SG finish, and can't figure out why you have "rough" patches or "crap" in your finish.
Here is my recommendation for a finish which is smooth, shiny, and as free from defects as possible(I am also taking into consideration cost as well)
1. Wash car (some quality car wash) and dry.
Stick your hand in a cellophane cig wrapper or plastic bag. GENTLY run your fingers down the car while wrapped in cellophane or plastic. Do you feel "pebbles", "bumps", or "rough patches"? If so, consider the clay in step 2. If she's smooth as glass, then go to step 3.
2. Clay the car. Mother's makes a kit for 18.00 that you can buy at Pep Boys. Autozone or Trak may carry it also. You can find tips for claying on this site.
3. Check the paint for swirls. If you see scratches/swirls, you might want to use a 3M or other product to remove them. It's up to you. AIO will highlight swirls in my experience, and then SG will work to fill them in. I find best thing to do is "remove" or hide the swirls with 3M or other product first, then AIO, then SG.
4. After claying/swirl removal you can wash again, or just use AIO. I normally wipe down the car after claying with a MF cloth misted with a quick detailer. I wipe gently and remove any clay residue. The AIO then cleans the paint and removes any other items.
5. Layer on up to 3 or 4 or 5 coats + of SG waiting at least 12 to 24 hours in between coats. I apply SG, allow 1 hour to dry, buff off. Wait 24 hours, then apply next coat. Not to brag, but I have a garage to do this in. If you don't, this method is debateable as you rely upon weather etc to be friendly. I find waiting the 24 hours gives me a deeper shine, and I think a better bond of the SG layers. I know this much. When I try back to back layers of SG, I have seen "hazing" or "gumming" of the Klasse SG, and that's using one to 1.5 ounces on a car. The 24 hours seems to "harden" the Klasse and lets the SG layer on.
So, claying only costs you 18.00 more. I just clayed my 2002 Ford F-150 Supercrew with 5 layers of SG on it. I clayed the truck because after claying my 2001 Mustang, I realized how much SMOOTHER the stang paint was even though I had five coats of SG on the truck! I might have removed one to two layers of SG with the clay, but I plan to layer two or more layers this week.
Here's the kicker:
I had already deep cleaned my 2002 F-150 with ABC and Pinnacle Paint Cleansing Lotion prior to AIO or my first five layers of SG. I think it shows that even with "chemical" cleaning, sometimes clay gives that extra touch. I think you will find the clay gives you a really smooth surface to work with, and that will enhance your shine and slickness once you apply AIO and SG.
Please respond with any questions.
SJ