Here is an image, at the top the old platform (v1.9.1.9), at the bottom the new platform (v1.9.2.9).
Same rig and graphic card.
Link
Edit : Someone on Github pointed out the following.
0.13239-4%=0.1270944 (2%third party dev fee + 2% NiceHash)
0.13239-5%=0.1257705 (if 3% thrid party dev fee)
Maybe NBMiner fees are not respected... Or it is the estimation of the btc value. You can see the 1btc=xxusd if you put your cursor on the 3 black bubuls on the right bottom. (this value can be wrong)
I came out with the 20% difference, comparing the "EUR/Day" value.
The estimation of the BTC value isn't the same between v1.9.1.9 (9125 EUR/BTC) and v1.9.2.9 (8316 EUR/BTC).
That person is correct a second time, it is a 5% difference, if we compare the mBTC/Day" value.
That would mean that the fees are taken into account and deducted in the "mBTC/Day" value in v1.9.2.9, but not in v1.9.1.9 (I'm waiting for a confirmation for that assumption).