I would say, for sure, starting will discharge the battery briefly, but the regulator should bring it back up if it's throwing 14.2 volts. But how long is your daily ride, ten or fifteen minutes? And stop and go traffic where the voltage at idle may be discharging (   12.4 volts for an AGM is quite flat (65%).   I would do a couple things: first, measure voltages 1) key off, 2) after 3 minutes of high beam, 3) during cranking, 4) at idle, and 5) at various rpm (2000-4500)