Kuffie, I have learned to take your long numerical posts as something to look at from a distance.
If Spit V is a dominant Spitfire late war, you are basically suggesting that their loss rate is not so much. Or are the IX's post war?
There are others that know these numbers vastly better than both you and me, and I have no doubts that your post will be dealt with properly.
This Mk V theory of yours actually has been tortured into other numbers than you started with, - but this is history, not a god-damned haggling contest. So bite the bullet, - there were more of the IX series produced than the V, and their loss rates, I belive, and therefor operational life, came out better, as they should have.
BTW, many RAF squadrons already had a batch of IX's within them with the bulk being V's, - replacements were not always complete. I think some "swap" dates refer to the date when the squadron was fully equipped with IX's. I feel sure that Guppy or Milo know this, and stay in your boots please, for when Guppy gets annoyed, it means you are pissing against the wind.