diff --git a/src/actor.h b/src/actor.h
index 5574f864a..ac51b6836 100644
--- a/src/actor.h
+++ b/src/actor.h
@@ -402,7 +402,7 @@ enum EBounceFlags
 	BOUNCE_Ceilings = 1<<2,		// bounces off of ceilings
 	BOUNCE_Actors = 1<<3,		// bounces off of some actors
 	BOUNCE_AllActors = 1<<4,	// bounces off of all actors (requires BOUNCE_Actors to be set, too)
-	BOUNCE_AutoOff = 1<<5,		// when bouncing off a floor, if the new Z velocity is below 3.0, disable further bouncing
+	BOUNCE_AutoOff = 1<<5,		// when bouncing off a sector plane, if the new Z velocity is below 3.0, disable further bouncing
 	BOUNCE_HereticType = 1<<6,	// goes into Death state when bouncing on floors or ceilings
 
 	BOUNCE_UseSeeSound = 1<<7,	// compatibility fallback. This will only be set by
@@ -414,6 +414,7 @@ enum EBounceFlags
 	// MBF bouncing is a bit different from other modes as Killough coded many special behavioral cases
 	// for them that are not present in ZDoom, so it is necessary to identify it properly.
 	BOUNCE_MBF = 1<<12,			// This in itself is not a valid mode, but replaces MBF's MF_BOUNCE flag.
+	BOUNCE_AutoOffFloorOnly = 1<<13,		// like BOUNCE_AutoOff, but only on floors
 
 	BOUNCE_TypeMask = BOUNCE_Walls | BOUNCE_Floors | BOUNCE_Ceilings | BOUNCE_Actors | BOUNCE_AutoOff | BOUNCE_HereticType | BOUNCE_MBF,
 
diff --git a/src/p_map.cpp b/src/p_map.cpp
index 6f5496054..1dc77dad2 100644
--- a/src/p_map.cpp
+++ b/src/p_map.cpp
@@ -1822,7 +1822,7 @@ bool P_TryMove (AActor *thing, fixed_t x, fixed_t y,
 				{
 					goto pushline;
 				}
-	            if (thing->flags6 & MF6_STEPMISSILE)
+				if (thing->flags6 & MF6_STEPMISSILE)
 				{
 					thing->z = tm.floorz;
 					// If moving down, cancel vertical component of the velocity
@@ -2925,7 +2925,7 @@ bool P_BounceActor (AActor *mo, AActor *BlockingMobj, bool ontop)
 				if (abs(mo->velz) < (fixed_t)(mo->Mass * mo->GetGravity() / 64))
 					mo->velz = 0;
 			}
-			else if (mo->BounceFlags & BOUNCE_AutoOff)
+			else if (mo->BounceFlags & (BOUNCE_AutoOff|BOUNCE_AutoOffFloorOnly))
 			{
 				if (!(mo->flags & MF_NOGRAVITY) && (mo->velz < 3*FRACUNIT))
 					mo->BounceFlags &= ~BOUNCE_TypeMask;
diff --git a/src/p_mobj.cpp b/src/p_mobj.cpp
index 7bb67a529..a014aa5f8 100644
--- a/src/p_mobj.cpp
+++ b/src/p_mobj.cpp
@@ -1444,10 +1444,14 @@ bool AActor::FloorBounceMissile (secplane_t &plane)
 		if (abs(velz) < (fixed_t)(Mass * GetGravity() / 64))
 			velz = 0;
 	}
-	else if (plane.c > 0 && BounceFlags & BOUNCE_AutoOff)
-	{ // AutoOff only works when bouncing off a floor, not a ceiling.
-		if (!(flags & MF_NOGRAVITY) && (velz < 3*FRACUNIT))
-			BounceFlags &= ~BOUNCE_TypeMask;
+	else if (BounceFlags & (BOUNCE_AutoOff|BOUNCE_AutoOffFloorOnly))
+	{
+		if (plane.c > 0 || (BounceFlags & BOUNCE_AutoOff))
+		{
+			// AutoOff only works when bouncing off a floor, not a ceiling (or in compatibility mode.)
+			if (!(flags & MF_NOGRAVITY) && (velz < 3*FRACUNIT))
+				BounceFlags &= ~BOUNCE_TypeMask;
+		}
 	}
 	return false;
 }
diff --git a/src/thingdef/thingdef_data.cpp b/src/thingdef/thingdef_data.cpp
index bafa0fa8b..f4ee1eeda 100644
--- a/src/thingdef/thingdef_data.cpp
+++ b/src/thingdef/thingdef_data.cpp
@@ -256,6 +256,7 @@ static FFlagDef ActorFlags[]=
 	DEFINE_FLAG2(BOUNCE_AllActors, BOUNCEONACTORS, AActor, BounceFlags),
 	DEFINE_FLAG2(BOUNCE_ExplodeOnWater, EXPLODEONWATER, AActor, BounceFlags),
 	DEFINE_FLAG2(BOUNCE_MBF, MBFBOUNCER, AActor, BounceFlags),
+	DEFINE_FLAG2(BOUNCE_AutoOffFloorOnly, BOUNCEAUTOOFFFLOORONLY, AActor, BounceFlags),
 
 	// Deprecated flags. Handling must be performed in HandleDeprecatedFlags
 	DEFINE_DEPRECATED_FLAG(FIREDAMAGE),