so i just fought you, I was slightly active (i'm guessing you were not) my SPF at the end was .92 and yours was .95 and I won. This seems in line with what I have noticed, that, in a way the final SPF doesn't matter, but who is simply most active in that hour. For instance, lets say I started with an SPF of 70 and you were at 95; I am active for that hour and raise my SPF to 85 - even though your overall SPF is higher than mine (95>85) if I was more active in that timeframe, I will still win - that seems to be the pattern. It feels like it is actually comparing my active SPF vs your active SPF in that time frame; my SPF for that hour would have been 15 whereas yours was 0.