Incorrect matched total

Hi There,

We are using PS 9.1, we recently had a new invoice scanning system that feeds directly to PS vouchers. One I noticed is that when the unit price is swapped with quantity )E.g. 1 quantity X $100 price was inverted to 100 quantity and $1 price) People soft uses data from receipt and voucher to calculate the matching total in the activity summary (I am unable to attach image).  This causes the Merchandise Matched total to increase a whole lot. Is this as designed? Please advise.

Thanks,

Dante