Earliest possible delivery date in PO GR

Hello. I'm using confirmation control in PO. I want to use message class M7, number 254 as a warning during GR via MIGO. However, the "Earliest possible delivery date" that the system takes is the request del. date from the PO and not the confirmed del. date. Is there a way that the confirmed date (where exist) will be taken into considaration? Appreciate any help on this topic