diff --git a/src/slope_anchors.c b/src/slope_anchors.c
index ff1504a37..add9a33b7 100644
--- a/src/slope_anchors.c
+++ b/src/slope_anchors.c
@@ -118,11 +118,6 @@ anchor_height
 		const mapthing_t * a,
 		const sector_t   * s
 ){
-	if (a->extrainfo)
-	{
-		return a->options;
-	}
-	else
 	{
 		INT16 z = ( a->options >> ZSHIFT );
 
@@ -194,6 +189,7 @@ get_anchor
 		mapthing_t               **      anchors,
 		fixed_t                     distances[3],
 		const struct anchor_list  * list,
+		const INT16                 tag,
 		const vertex_t            * v
 ){
 	size_t i;
@@ -202,7 +198,7 @@ get_anchor
 
 	for (i = 0; i < list->count; ++i)
 	{
-		if (list->points[i] == v)
+		if (list->points[i] == v && list->anchors[i]->extrainfo == tag)
 		{
 			for (k = 0; k < 3; ++k)
 			{
@@ -243,14 +239,15 @@ get_sector_anchors
 		mapthing_t               **      anchors,
 		fixed_t                     distances[3],
 		const struct anchor_list  * list,
+		const INT16                 tag,
 		const sector_t            * sector
 ){
 	size_t i;
 
 	for (i = 0; i < sector->linecount; ++i)
 	{
-		get_anchor(anchors, distances, list, sector->lines[i]->v1);
-		get_anchor(anchors, distances, list, sector->lines[i]->v2);
+		get_anchor(anchors, distances, list, tag, sector->lines[i]->v1);
+		get_anchor(anchors, distances, list, tag, sector->lines[i]->v2);
 	}
 }
 
@@ -258,7 +255,8 @@ static mapthing_t **
 find_closest_anchors
 (
 		const sector_t           * sector,
-		const struct anchor_list * list
+		const struct anchor_list * list,
+		const INT16                tag
 ){
 	fixed_t distances[3] = { INT32_MAX, INT32_MAX, INT32_MAX };
 
@@ -280,12 +278,12 @@ find_closest_anchors
 		for (i = 0; i < sector->numattached; ++i)
 		{
 			get_sector_anchors
-				(anchors, distances, list, &sectors[sector->attached[i]]);
+				(anchors, distances, list, tag, &sectors[sector->attached[i]]);
 		}
 	}
 	else
 	{
-		get_sector_anchors(anchors, distances, list, sector);
+		get_sector_anchors(anchors, distances, list, tag, sector);
 	}
 
 	if (distances[2] < INT32_MAX)
@@ -311,12 +309,13 @@ find_closest_anchors
 
 		I_Error(
 				"(Control Sector #%s)"
-				" Slope requires anchors near 3 of its target sectors' vertices"
-				" (%d found)"
+				" Slope requires anchors (with Parameter %d)"
+				" near 3 of its target sectors' vertices (%d found)"
 
 				"\n\nCheck the log to see which sectors were searched.",
 
 				sizeu1 (sector - sectors),
+				tag,
 				last
 		);
 	}
@@ -324,9 +323,11 @@ find_closest_anchors
 	{
 		I_Error(
 				"(Sector #%s)"
-				" Slope requires anchors near 3 of its vertices (%d found)",
+				" Slope requires anchors (with Parameter %d)"
+				" near 3 of its vertices (%d found)",
 
 				sizeu1 (sector - sectors),
+				tag,
 				last
 		);
 	}
@@ -367,6 +368,24 @@ new_vertex_slope
 	return slope;
 }
 
+static void
+slope_sector
+(
+		pslope_t                ** slope,
+		sector_t                 * sector,
+		const INT16                flags,
+		const struct anchor_list * list,
+		const INT16                tag
+){
+	mapthing_t ** anchors = find_closest_anchors(sector, list, tag);
+
+	if (anchors != NULL)
+	{
+		(*slope) = new_vertex_slope(anchors, flags);
+		sector->hasslope = true;
+	}
+}
+
 static void
 make_anchored_slope
 (
@@ -384,7 +403,6 @@ make_anchored_slope
 	const int side = ( flags & ML_NOCLIMB ) != 0;
 
 	sector_t   *  sector;
-	mapthing_t ** anchors;
 
 	if (side == 0 || flags & ML_TWOSIDED)
 	{
@@ -392,17 +410,15 @@ make_anchored_slope
 
 		if (plane & FLOOR)
 		{
-			anchors = find_closest_anchors(sector, &floor_anchors);
-			sector->f_slope = new_vertex_slope(anchors, flags);
+			slope_sector
+				(&sector->f_slope, sector, flags, &floor_anchors, line->tag);
 		}
 
 		if (plane & CEILING)
 		{
-			anchors = find_closest_anchors(sector, &ceiling_anchors);
-			sector->c_slope = new_vertex_slope(anchors, flags);
+			slope_sector
+				(&sector->c_slope, sector, flags, &ceiling_anchors, line->tag);
 		}
-
-		sector->hasslope = true;
 	}
 }