Lyra2v2 is problematic for nvidia, the miner itself reports 30% higher hashrate than actual. Perhaps you should add a penalty for the algorithm on nvidia or check what miner gives a real hashrate.
Weird, mine typically reports at the pool about what my miner is telling me it is. Mine say 55mh/s and typically reports between 45 and 65 (sometimes even higher in periods of good luck) at the pool.
What miner do you use? Excavator is the highest at the benchmarks but the real hashrate is much lower.