These cars adjust depending on fuel used. 93 being Max fuel. You can put race fuel in it. Say 110 octane but it isn't going to do much if nit hurt it. The computer can only adjust +/- 3 degrees of timing. So it not going to do nothing really on a stock car. They have showed these cars made more power on 93 over 87. And it is very common for them to dyno base on 87. Then tune on 93 and dyno to show bigger gains.
On a FI car putting a little race fuel in with your 93 can make a big difference. That 3* of adding timing can be 40whp.