Try out the following:
XF3 followed by Gold Armor- try to throw gold lances as fast as you can. Notice that if you set the dummy to Auto Guard, you cannot keep them locked down in blockstun.
Gold Armor followed by XF3- do the same and notice how you can throw lances about 50% faster.
As far as I can tell, this bonus applies to all levels of X-Factor. XF2 activated after Gold Armor is literally faster than XF3 activated before Gold Armor.