Generally if the money has different levels (which, in your example it sounds like 21 through 40 each received the same amount before going up at 20) and not a continuous escalation of payouts, the game WILL go HFH at each level's bubble.
Stalling once in the money usually isn't as big of a problem. Sure, you'll have ONE person, short-stacked, stalling to try to make it to the next payout, but you WON'T have the rest of people collaborating with that short-stack to make sure they make it to the next level. Once in the money, the sooner the short-stack goes out, the closer the others are to 1st place.
As I mentioned, the ONLY place I've seen stalling be an issue is in satellite tourneys where x people move on, and then ONLY where the satellite is a freeroll (such as the UB TEC Freeroll). I've played the UB WSOPVIP $5 and am playing the $5 TV qualifiers and nothing like that happens. Sure, you've got the guy with a stack of 400 chips hanging on by the fingernails to make the cut (I *know* this!
) and they will often try to stall. But once HFH starts, stalling becomes completely pointless.