Changing Differential Oil….Question

I have a 2000 Honda Rancher TRX350FE. I went to change the differential oil in the front and rear and ended up using twice as much oil as what the capacity "should be". Should’ve only needed 12oz total and used about 24oz. It all went in and isn’t leaking, so I’m wondering what’s goin on. Does it mean the seals are out?? Thanks for any advise here.