Thanks, That is what I suspected. Back in the day I mined with Slush and there was a slight variance too.
Setting up on litecoinpool.org with an L3+ was as easy as can be and rewards are about 1.5 LTC /day with 500MH/s.

not sure what you mean. My L3's and L3+'s are mining what they say they are mining on the pool...assuming I have this correct?