It's not the Verbote that are being deducted; it's the sum(s) of money that they represent - the Inkassierungen that aren't allowed. That's how I understand the sentence.

oh..oh..i think i got wht you want to say.

it seems like this:
Here, the relevant prohibited encashments are deducted once in a month after processing the billing-relevant data for the month.

#2: Hört sich inhaltlich korrekt an!