The miles for upgrade are always the same. HOWEVER - you need to have purchased a fare class that allows upgrade. These are:
Economy: Y B H K M
Premium: W R
Business: J C D I (all)
Heavily discounted fares are usually not in these fare classes (unless you're looking at Business class).
Award charts and T&C are here:
http://www.asiamiles.com/am/en/redeem/charts#2