Question about ETH mining on ethermine.org pool...

My rig within Claymore is hashing at ~198MH, but the pool is displaying the following:

Hashrate as reported by miner to pool = ~198MH
Effective current hashrate = 174MH
Avg Effective hashrate 24hr = 175MH

I know some variation between miner and pool is expected, but >20MH seems like a lot to me!!!

Anyone experienced this before?     Fixes?  Or known issue?  Thanks!!!