DATEDIFF When Usinf IF Argument

OK, I think that I would do something like this:

CAPA Planning Days = 
  VAR __RecordSource = MAX(CAPATable[Record_Source])
  VAR __Status = MAX(CAPATable[Status])
RETURN
  SWITCH(
    TRUE(),
    __RecordSource = "Audit" && __Status = "Closed-Door",DATEDIFF(MIN(CAPATable[DATE_OPENED]), MAX(CAPAPlanFirstApproval[FirstDate]), DAY),
    __RecordSource = "Audit" && __Status = "Closed-Correction",DATEDIFF(MIN(CAPATable[DATE_OPENED]), MAX(CorrFirstApproval[FirstDate]), DAY),
    __RecordSource = "Quaity Issue",DATEDIFF(MIN(CAPARequiredTable[DATE_PERFORMED]), MAX(CAPAPTable[CAPA_PLAN_APPROVAL_ON]), DAY),
    BLANK()
  )