Reference the voltage variation.....
Also take into account, that to crank and start a 3.2 litre engine requires ENOURMOUS current and energy from the battery.
This used power has to be replaced by the alternator, and the alternator can only do this by overcoming the opposing battery voltage to get the Amps back into the battery.
Once the cranking amps are replaced back into the battery, the battery and alternator voltages will equalise and settle down.

What you have discovered and noticed is perfectly normal.