Why don't people/Judges use the 10-10 round very often?

[:::PSL:::]

I know people give Teddy Atlas shit for scoring lots of rounds even (I can't say, I havn't watched any fights where he is guest judging) but I scored a couple rounds even in the Pac JMM fight just because it was so hard to differentiate and it was back and forth action.
Lots of people were arguing here about the first round and everyone admitted it was hard to score so why not a 10-10 round? Is it because judges are encouraged to find a clear cut winner of a round to help with scoring a fight?

I guess what most judges are looking for is the QUALITY in the fight, not QUANTITY.

e.g.

JMM won the overall HBO compubox percentage. But Manny won the RBR scoring because he was the aggresive and actually the one whose been doing more damages against Marquez.