I see often PCC being defined for every part that should be separated. I see the following lines for example 25% for one gateway and 75% for the second gateway.
Then I see these kind of PCC rules:
PCC line 1: pcc 4/0 ==> connection mark gateway-25 if not already connection marked
PCC line 2: pcc 4/1 ==> connection mark gateway-75 if not already connection marked
PCC line 3: pcc 4/2 ==> connection mark gateway-75 if not already connection marked
PCC line 4: pcc 4/3 ==> connection mark gateway-75 if not already connection marked
Connections now gets split in one part for gateway-25 and three parts for gateway-75 making in total 100%
In fact splitting the connections in two parts. One of 25% and one of 75%. If you want to have a 75% part then you can subtract 25% from 100% and you are left with 75%.
Why not apply that that also to PCC? The lines will be then like this and the strike-trough lines can be omitted in the final version of course.
PCC line 1: pcc 4/0 ==> connection mark gateway-25 if not already connection marked
PCC line 2: pcc 4/1 ==> connection mark gateway-75 if not already connection marked
PCC line 3: pcc 4/2 ==> connection mark gateway-75 if not already connection marked
PCC line 3: pcc 4/3 ==> connection mark gateway-75 if not already connection marked
Traffic not already connection marked ==> gateway-75
You are now having the same result by replacing three lines by one line. That line marks the traffic not yet marked by the pcc 4/0 line which is the remainder of 75%.