Must hit jackpot liability

Does anyone have a clue how gaming decides what the value of progressive must hits is?

I would guess the return includes contribution to progressive (i.e. meter) and probably the base jackpot * the probability of hitting the jackpot on a given spin.

On one hand, assume the must hits have a negative expectation, then there would be nothing to transfer. On the other hand, the machine is holding back a value, that is said to be guaranteed to hit at some point. I'd think the value should be between the increase and the guaranteed value, but that's not much of an answer. It's especially tricky when the range is very small with large meter rates.

Just realized I might not have been clear for everyone, I'm referring to the instance when a must hit progressive is removed from the floor.

Now I think about it, maybe the perfect way would be for the casino to have someone play it max bet until each progressive hits once. Then if it took a certain amount of dollars bet, they would know. Otherwise, there would be no way of knowing when the machine would hit. Don't bet on that.