It is not improbable you did nothing wrong and Crown had an off-day on the battery line. IMHO establish a rational maintenance voltage value, disconnect the batteries from loads, and verify the batteries do not eat more ampere hours than their due (self discharge) at their particular ambient temperature.
For example if I were maintenance charging a 100 amp hour battery using the temperature compensated float voltage as recommended by the manufacturer -and- the manufacturer claimed a 5% month, self discharge rate at that temperature-
and-
Your amp hour meter tattles the battery eats second and third helpings, I would start looking.
