Interesting.
I just loaded a single mission with a few ships in it with new skins.
I set the unit roster files for each texture such that one was good from 1901 til 1940, then the next from 40 to 41, 41 to 42, etc.
I put 3 in the single mission, with the cfg date for each merchant set such that 1 should have had skin 1, then another skin 2, and the last skin 3.
Even though the mission date was 1944, all showed up with the pre-1940 skin.
OK, then I make all the dates 1901-1999 and try again. This time I set the frequency for skin 1 = 0.3, skin 2 = 0.3, skin 3 = 0.4
And I got 2xskin 1, and 1xskin 3!
Frequency might well work. In fact, setting frequency = 1 might FORCE using the first skin with an available date... must test. The ability to have many many skins will become important soon
