I don't have the numbers memorized and it's been awhile since I made those changes to my mod, but if memory serves me correctly Vasari squadrons build faster than the others...and Advent squadrons build slower...the XP for destroying individual SC is also screwy...that there are different numbers of SC per squadron makes some squadrons more valuable XP wise than others...
Some of these issues will only apply to say, Vasari bombers vs. Advent bombers (one being built significantly faster or worth more XP), and some only apply to the fighters...
When I get a chance I'll look at the entity files and get more details, but basically if you just multiply the values associated with individual SC by the number per squadron, you can get a fair comparison among the factions' SC capabilities...