The alternator in my 2007 MCS is claimed to be overcharging the battery causing intermittent no starts and some electrical glitches. At idle and with full load it registers 15.7-15.3 Volts. So the shop recommends to change the voltage regulator.

Are the voltage readings really too high for a 150A that may cause intermittent hard starting (all with a hot engine) and electrical glitches (i get faults on the gauge indicating that most of my exterior lamps are busted but all work fine even the plate lamps)? It seems the fuel pumps are working fine as there are no stumbling or erratic idling once the car starts. Battery is new.