treadigraph and others,
This old puzzle in my log entries may deepen the confusion !
(20 Sqn, Valley):
1950 April 17...Spitfire IX .TD254
...........18...Spitfire IX .TB379
...........20...Spitfire XVI RW 351
...........27...Spitfire IX .TD254
......July 25...Spitfire XVI TD254
This was not queried either by Flight or Squadron Commander on the Monthly Summaries. As I remarked earlier in "Pilot's Brevet in WWII" (Military Aviation Forum): "I would certainly have known the difference, or had it sharply pointed it out to me !"
All subsequent Spitfires were logged as XVIs. It would seem that nobody bothered with the difference any more.
Possibility: if a Merlin Spit were re-engined as a Packard Spit, would a IX turn into a XVI ?
(Just asking). Danny.