Alternator or Voltage Regulator going out?
 

Still tinkering with my miata N/A attempting to get something that resembles a good tune. Looking through some logs, even older logs I've discovered a bad trend.. My voltage isn't what I think it should be.

Maximum voltage during the afternoon in a 75mph cruise on the highway is 13.2 - 13.7 volts, fluctuating pretty quickly between them... Shouldn't it be more like 14 - 14.7 volts? Or this this pretty normal for miata?

13.2v to 13.7v is normal, you don't want to overheat/overcharge the battery.