It is not a dumb question. And the answer is yes.
Well, it's not quite that simple. There is another factor, the variance, to consider. The higher the variance, the more spins it takes to reach the 95% average.
This often causes problems, with a player complaining they played 200 spins on a high variance slot and got a return under 50%, and that this somehow means the slot has cheated them.
Strictly speaking, in the above case a 95% payout is reached at infinity spins. Some slots can have such high variance that even 10,000 spins can produce a significant departure from a quoted average payout. There is no way to predict whether a specific session of n spins will produce a payout over, or under, the quoted average (assuming the slot is random).
For simple slots, it is possible to calculate this variance, as well as the expected return, and come up with some probabilities that will describe what can be expected on average from a session of n spins - this might take the form of something like "you should be within x% of the average payout in y% of sessions each of n spins"
Slots with pick bonus rounds are harder to calculate values for, since it is not possible to work out the probabilities of the bonus awards, however slots with free spins and multipliers are only a little more complicated, and exact probabilities can be calculated on the assumption the slots are unweighted and random, which applies to most online video slots in "honest" casino software. Video versions of "classic" slots are different, these are usually weighted, and Microgaming's "Fruit Machines" are most certainly NOT random!
