In the first auction opener already bid 1♠ telling partner of 5 spades yet many experts would routinely bid 4♠ over 4♥ with pretty much every 6-4 they have (and was worth opening). Note that if the 1NT contains 3 cards in a limit raise he would definitely bid 4♠ over 4♥ so opener is catering to the case where 1NT has 2 card support.
In the second auction it is the first chance to bid spades and the diamond bidder could have between 0 and 4 spades and will definitely not bid spades with the favourable case of 3-4. I disagree with you that in this case you need substantially better/longer spades than the first case to bid 4♠.
So overall I think we differ on the question what class of hands the 4♠ bidder will hold. I think it changes the parameters of the 5 level pull a lot. And I suggest we agree to disagree
