Adjustment to Mid Stakes

[Kico9]

I have been playing 5-10 holdem for about two years on the SunCruz boat out of Cape Canaveral. On average I win about $200 on a 4 1/2 session using the Miller book. Over the last 4 months I have started to play 10-20 using the same strategies but have notice that my average has dropped to $100 a session. Besides moving back down to 5-10, what general adjustments should I make?