The .up, .dn, etc. will work like normal, it just means that you can't hit acceleration at some high value and go flying across the screen. You have to pay for every movement you get.
Imagine a bot does 5 .up store.
In the old veresion:
wow, the bot moves this far after infinity turns (that is, after friction stops it).
In the new version:
darn, that didn't get us far at all! I guess we have to keep expending energy to go forward.