diff --git a/core/loadpoint_plan.go b/core/loadpoint_plan.go
index 4c6d3ce47..13513f33a 100644
--- a/core/loadpoint_plan.go
+++ b/core/loadpoint_plan.go
@@ -169,7 +169,7 @@ func (lp *Loadpoint) plannerActive() (active bool) {
 
 	if active {
 		// ignore short plans if not already active
-		if slotRemaining := lp.clock.Until(activeSlot.End); !lp.planActive && slotRemaining < tariff.SlotDuration && !planner.SlotHasSuccessor(activeSlot, plan) {
+		if slotRemaining := lp.clock.Until(activeSlot.End); !lp.planActive && slotRemaining < tariff.SlotDuration-time.Minute && !planner.SlotHasSuccessor(activeSlot, plan) {
 			lp.log.DEBUG.Printf("plan: slot too short- ignoring remaining %v", slotRemaining.Round(time.Second))
 			return false
 		}