Those are the weight reduction amounts. The haste amount was known to be a third of the weight reduction of the quiver, which is confirmed here:
http://www.zlizeq.com/Game_Mechanics...sists_and_Mods
Tailored Quiver at 22% WR and Quiver at 20% WR confirmed here:
http://www.monkly-business.net/forum...31&postcount=2
Fleeting Quiver at 60% WR (i.e. 20% haste, stackable with worn/spell haste) confirmed here (page copyright 2001):
http://home.roadrunner.com/~less3d/e...leeting_quiver