I tend to leave my ribs in foil after a 3h/ (3 1/2h) smoke btw .45min and 1 1/2 hour and the last 1h to 2h off foil with finishing sauce. The issue is that its "out side temperature dependent", "grill dependent", "rib cut" and "personal preface" dependent. The idea is to become consistent with your smoker, rub, sauce , your rib preference.
Foil (steaming) cuts down on grill time and produces tender ribs, however it should only be used in short amounts of time. If your over foiling you will offset the trinity of rib balance consisting of ...Outside texture, Inside moistness and Rib flavor.