@soundslikethis
I think my "length and width" comment holds true for this current year (2014-2015) Swingman, with the new material and heat pressed numbers. The Red Zone was a release from last year, where they only shortened the length, but respective widths remained the same (like the difference in Soul 7996 and 7484). Which kinda strengthens my point, another year...ANOTHER changing of sizing. Most of my collection is Heat as well. So here we have the Heat throwbacks...red was 2012/13, black was 2013/14. These are both size M, as you can see the widths match up fairly well, but the length has changed.
Then we have the Back in Black, size M (2011/12) and this years Black Tie, size L. So you can see how now widths AND lengths are different.
Seems as if it all moved 1 size, roughly. L is old M, XL is old L. Different teams have different cut jersey's so it might vary team to team obviously.