You have to remember, units are built to be cost effective tor the manufacturer. I have found the capacitors for compressors for most systems have voltages of over 370 vac applied to them when the system is operating. This voltage is measured across the capacitor. in the case of the dual cap. it is measured from common to hermetic or common to fan.
the voltage rating of the capacitor is the insulation value and should not be below whatever is created when the unit is operating. We only stock or apply 440 vac capacitors if we have the choice.
These seem to last better than 370 vac as the insulation value is greater and will allow higher voltages. Check yours to see if it is a 370 vac rated cap then change it to a 440 vac if so