Thanks Conn.

Mileage drop is so small that it may often be offset by changes in driving patterns, running the A/C, and so on.

I'll trade 1 extra MPG for smoother running any day.

FYI - last tank of got 26.88 MPG on a mix of city/highway with AC running. On the last tank of B20 it was 26.01. I cannot complain.