R03B551, R03B50D, F03B13Z1 RUAG not totaling to RUCKAM

Occasionally we have customers that have remittances with a distribution into our lockbox where the total of the distribution RUAG does not match the check amount RUCKAM when loaded into the F03B13Z1.  The R03B551 and R03B50D do not seem to care and create a 26 Chargeback for the under/overpay whichever way you want to look at it.  Then when working the RB, we receive an error about going negative when trying to delete the RB.  We do have a workaround, but my question is should the R03B551 or R03B50D allow this or is there a processing option or SAR to either progran to prevent this