I'm sure you've also had long sessions where you hit many full houses and flushes, but don't hit quads or better.
Or perhaps you've had sessions where you set a stop-loss of a certain amount, and the extra money you would have won in the additional flush/full house payout would have been the credits that would have hit something big. So those extra payouts also give you "free hands" when you are playing to a stop-loss point.
This disdain for good flush/full house paytables is the reason we are seeing such a degradation with every passing year. Even knowledgeable VP players like Alan find ways to reason to themselves that paytables aren't so important.