Sorry chaps, that wouldn't work unfortunately
I'll add session numbers to the scoring system for the GP's this year so we can see what difference it makes, but having session specific percentages could introduce some crazy results.
What you've got to consider is that a GP is really 4 competitions in one.
Firstly it's an individual competition where trophies are given out for the highest score in each class / category on the day - that result is based on targets hit, not percentages.
Then we have Showdown qualification, and that's based on targets hit and countback, not percentages.
Then we have the Team competition, again that's based on targets hit not percentages.
and then we have the GP series league table, which is the only part of the competition that is based on percentages.
If you changed the percentage system to make it session specific, what you might see is that the person taking away the 1st place trophy for C grade (for example) not ending up being the person at the top of the C grade league, that would be a bit crazy wouldn't it? In fact, it would be possible for someone to take a 1st place trophy for every GP and still end up not winning the league for their grade. That would be crazy surely?
Since the only part of the competition that uses percentages is the series league table, there's a good chance that any major differences between AM and PM sessions would quite likely even themselves out by the end of the series.
It'll be interesting to see how much difference it makes, so I'll add the session number to the results this year so Si can use the info.