Two coats of Z2pro lasted 13 months (and was still going, kinda...) on my wifes car which was washed maybe 3 times over that time, and recieved Z8 once (at about the 2 month mark) so I believe you.
I have been testing several different sealants (and will do a write-up with pics soon) and I will tell you all the sealants I tested (Zaino Z5pro, Zaino Z2pro, Werkstatt Prime/Trigger, Ultima, Wolfgang, Meguiars #21, and CG JetSeal 109) that Zaino EASILY outlasted all of the others. Infact, on my hood, the Z2 and Z5pro sides are still going very strong (at 5 months) where the others are long gone.
JetSeal fell off the quickest at about 6 weeks...
Wolfgang fell off right behing at about 7 weeks...
Meguiars #21 fell off at 10 weeks...
Ultima fought well for 14 weeks, then left quickly
JW twins are starting to slow down (weakened beading but still there)
Zaino Z2 and Z5pro have shown no degradation yet (16 weeks)