$100 HUSNG: Push Expected Value?

[Nichomacheo]

This is a cross post, since hu forum is dead!

I'm not very good at doing the math for this, so I'd appreciate any feedback:

PokerStars No-Limit Hold'em Tourney, Big Blind is t20 (2 handed) internettexasholdem.com

Button (t1800)
Hero (t1200)

Preflop: Hero is BB with 7[img]/images/graemlins/spade.gif[/img], 9[img]/images/graemlins/spade.gif[/img].
<font color="#CC3333">Button raises to t40</font>, Hero calls t20.

Flop: (t80) K[img]/images/graemlins/club.gif[/img], 9[img]/images/graemlins/heart.gif[/img], A[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">Button bets t80</font>, <font color="#CC3333">Hero raises to t160</font>, Button calls t80.

Turn: (t400) 6[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
Hero checks, <font color="#CC3333">Button bets t200</font>, <font color="#CC3333">Hero raises to t1000</font>, Button calls t800.

So here is the question. Given that I assume he will fold 60% of the time (and that he has A5), what is the EV of this move?

I'm getting something like .4(.3(1600)-.7(800)) + .6(600) = +328?

The thing I'm not sure about are the 1600, 800, and 600 numbers. Can anyone confirm or explain to me what I am doing wrong? I cant wrap my head around it.

Nichomacheo