Oil in place is larger. The recovery factor connects the two. Contingent resources are volumes that have been discovered but are not yet commercial, because of price, a missing export route, or a decision not yet taken. Reserves are the remaining commercial slice, not the total that will ever have come out of the ground.
A proved volume is the firm end of that slice, the part the company will defend with a committed plan. Probable and possible volumes are less firm. An estimated ultimate recovery from a decline curve is a forecast of the well's total, and it is not automatically a reserves booking.