Deactivate Invoicing (MIR7 and MIR4) in a Purchase Order

Hi SAP Experts,

We have Purchase Orders (PO) for service (construction of building) to a vendor (contractor). We are using the Goods Receipt (MIGO) to receive the percentage accomplishment. However, we are using an ABAP program for invoicing instead of (MIR7 u2013 parking of invoice and MIR4 u2013 posting of invoice) since we pay a down payment to the vendor and we also have a retention amount. Our problem is if we use the ABAP program for invoicing to process payment, we can process it again using MIR7 and MIR4, which may result to double payment to the contractor. Is there a way where we can receive the goods (MIGO) and deactivate parking and posting of invoices (MIR7 and MIR4 respectively)?

Thanks,

Matt