Glow function question???

Can anyone help me with two issues? 
​#1- Does Glow factor in and adjust for cycles that vary from month to month? Last 3 cycles were 32, 31, 28. And I did go in and adjust my cycle day 1 each time. 
​#2- My OPK detected my surge on CD 16, which would make my most fertile time the day or two days after surge, right? Glow states that the most fertile day is different from the OPK. Not sure how to read it, so we just made sure to hit every day in the fertile week! ;)