A couple of things. If you have a multiple tee competition, you have a single CSS calculated adjustment, and that is applied to the SSS of each tee. Thus each CSS would be different, but the adjustment factor (-1, 0,+1,+2 etc) would be the same for all.
For a mixed tee scratch event, the difference in the SSS of each tee is taken into consideration. The score of the player using the tee with the higher SSS is reduced by the difference in the SSS of the two tees. Say the Tees have an SSS of 72 and 75, if both players played to the difficulty of that tee, one would have a scratch 75 and the other a scratch 72. So the player on the SSS=72 tee would win. So the score for the player on the higher SSS has their score reduced by the difference to take that into account.
