Sorry but its too jumbled and different types of training and intensities.
Here are the only 5 pics I have from Gough's training. All 5 are Hard Intensity Match Practice and all with a strarting condition of >80.
Here are the 2 prior to accumulating SP for 6*
PS. at least 1 of these I think I used the booster after training but before taking the pic.
Here are the 3 after Gough accumulate the points required for 6*
(He actually only needed 26 sp but the last Match Practice popped 2 SP at once.)
I don't have pics of the last 2 sessions I mentioned in the previous post. And from that previous post you can note that 1 of the results as 5* was lower than 1 of those as a pseudo 6*. But that's to be expected because the variation of results 'within a star' is actually larger than the decrease. Thats why I take a more structured approach to comparing the same type and intensity over a longer time and comparing averages.
My samples of over 20 sessions on each of several different players put the decrease on attaining the next star somewhere between 20-30% but clustering just over 25%.
(I can't do any more because I know what the results will be over a longer period and with a larger sample.)
Not much else I can add.
PS. I have not actually found definitive evidence from my other training samples that condition has any impact on gains, but I have not yet looked closely at that and its another topic.