Yes, mixing is different. Here are some examples. Even 7.5 of TAC and 2.5 of -eNone is good. I typically add 7.5 of P75 to that, but it’s according to taste. It delivers very good buffering. Simply layering TAC and None by themselves isn’t as good. The None burns in a slow and stealthy way underneath the comfort of TAC. Women can be responsive to as little as 1 mcg or less None with a few mics T A C for comfort per each mic of None. A mixed spray delivers this well. My three 30 mL bottles yield 90 mL of mix. You can make a version with 75 and without and use it daily for months.