I agree with your statement. The float level change on it's own will only result in 1-2 MPH and few hundredths of a second difference. If the weather is close to the same then I would think it would run 13.39 @ 100.5 in the 1/4. The additional fuel on the top end will allow me to safely test adding in additional timing which might result in a .1 or more change in ET.
As someone mentioned earlier, only change one thing at a time and test, test , test...