There is a discussion going on in the New Hire Class Drop thread that is more relevant to this thread.....pay protection when a junior pilot converts before senior.

PWA Reference is 22.E.9

Point #1: the pilots in questions have to be from the same AE. If junior Pilot A gets awarded a new category back in the Oct AE, it has no bearing on senior Pilot B getting awarded the same category in the Feb AE.

Point #2: if the award was done via AE (not a VD or MD) then we look at going TO the same category.

Point #3: if the award was done via VD, then we look at the category they are coming FROM.

Exceptions when the senior pilot is NOT pay protected:a. he required training and the junior pilot did not
b. his conversion was delayed due to his failure to complete training
c. or his training is delayed:
1) at his request, or
2) at his request under Section 22 D. 8., or
3) due to his:
a) sick leave
b) military leave of absence, or
c) disability.
4) because he has not accumulated sufficient flight time to satisfy the requirements of FAR 121.436, as amended from time to time.

Section 22 D. 8 reads:

A pilot may indicate in his standing bid a:
a. minimum acceptable relative seniority ranking (by number or percentage) in the category (including his own category),
b. specification for “regular line only,”
c. willingness to be displaced in lieu of a pilot who is junior to him and in his category, or
d. desire to be converted, among pilots who hold an award from the same posting:
1) if awarded an AE, after more junior pilots holding an AE to the same category.
2) if awarded a VD, after more junior pilots holding a VD from the same category.
3) if awarded an MD, before more junior pilots holding an MD from the same category.

DISCUSSION:

1) I don't see retaining vacation specifically mentioned, but I assume it falls under the "training is delayed at his request" clause

2) it appears to me that length of training (short vs long requal) isn't a factor