I'm sorry PB, but you still confuse me, and probably the OP too. If you hook up two batteries in parallel, they will keep the same voltage at all times, whether being charged, in storage, or being used. So if the batteries are both 12V and have a useful voltage from say 12.5V to 13.5V, they will both reach 12.5V (or whatever the reasonable low voltage is) at the same time.
I agree this probably will not deliver 14AH in e-bike use, but it will equal or exceed the sum of the useable AH from the two batteries when used in a similar manner individualy.