2021 Mazda3 Turbo and CX-30 volt and mpg difference?

:
CX-5 2017 GT AWD
Been using the CX-30 since Saturday and I just noticed that with my daily route I average 26-29mpg in SPORT mode all the time, while M3TH is around 22-24mpg in non sport mode. Aside from this the voltage reading while running for the CX-30 is 13.7 while the M3TH is only 12.4.

The M3TH doesn't have any problem cranking in the morning will all the heaters, defoggers, steering wheel and seat heater at max setting.

Normal or something to be concerned about?