I came across the BHA handicappers blog on the Marois.
Excelebration ran to 125 in first place.
Cityscape ran to 122 in second, his 124 OR was for running over 1m 1f and 122 is a career high for him over a mile.
Elusive Kate ran to 119 in third, she was beaten 1 1/2l at 2lb a length which is a 3lb beating by a 125 horse which would give her 122 but she is deducted 3lb for the fillies and mare allowance, which brings her back to the 119 rating she achieved in winning the Prix Rothschild.
Moonlight Cloud in fourth OR 121 was judged to have had bad luck in running and was expected to have finished within 1/2l of Excelebration. which would have been a 124 run minus the 3 lb mares allowance.
Caspar Netscher in fifth was given a rating of 121 for being beaten 2l at 2lb a length.
So it seems the wage for weight allowance in GP1 s doesn't affect a horses official rating but the fillies and mares 3lb allowance has to be deducted when calculating the relative performances