Open Shove Math

Im trying to get my head around this and can’t seem to get the same answers to Icmizer. Basically I just want to know if Im doing something wrong... I choose a simple one to start with...Stacks are 500 and blinds 10/20 and its  AA vs 4.26% villain range (99+,AQs+,AKo).

Fold equity is                     490   (500-10sb)

Equity if called

Equity vs viallin range        82.8

Villain equity                      17.2

Villain will call                     4.26

If called and win               (82.8*4.26%)%*1000+490=525.27

If called and lose              490-(17.2*4.26%)%*1000=482.67

Total equity of shove 532.6 (490+525.27-482.67)

So shoving is t42.6

Now Icmizer comes out at t40.3

Can anyone explain why my maths is off, is it something obvious? I thought it could be something to do with card removal or drawing but I'm unsure. I tried factoring it in but still get a different answer to Icmizer.