if your removing both shocks you could try refitting them to the opposite side and see of your drop happens on the passengers side
do both the shocks look the same , are they quite new ? you might have different dampers , one being a standard and one a with a lower spring plate ( you should be able to see this clearly when they are both removed ).. it also might be worth checking to see if your anti roll bar linkages are both intact
my top guess would be dampers and springs ..