Zwift Racing Score and a 13 stages TOUR (doubts of ZRS)

Racing
1

Fellow racers, sorry for bothering:

We are in a terrific 13 stages tour (ZwiftPower - Login) and we have some doubts about the ZRS and the upper CAT that you select for a race.

ZRS force you not to select the lower CAT but not the upper one. Is there any difference if I (a C) choose to race in C, B or A? Am i compared and earning points based on everyone else (single start races all together)? Or just against people in my selected CAT?

People is getting upgrades and downgrades quite easily during the TOUR and there is the doub if the selected upper CAT would affect the ZRS score.

Can the system be exploited if i join upper CAT (A, for instance) as D in order to stop rising the score so quickly?

I am sorry, this is not my native language and i am not sure if I have been able to explain myself easily.

2

@Peter_Ruzicka_ZESP might know the answer to this

3

Another stage and I’m estimating the ranking is only based on their CAT rivals.

Same race, same rivals, same start:
Selected B CAT finish time: 31:46 - points down to 505 (finished 22 racers in B, and he finished 17th).
Selected C CAT finish time: 32:51 - points up to 508 (finished 50 racers in C, and he finished 15th).