diff --git a/package/qos-scripts/Makefile b/package/qos-scripts/Makefile
index 43225f919fbb390824774a7a764116d4f704dc22..676d4dd619a950f4efc0e1f471ab91550587d4f7 100644
--- a/package/qos-scripts/Makefile
+++ b/package/qos-scripts/Makefile
@@ -9,7 +9,7 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=qos-scripts
-PKG_VERSION:=1.1.0
+PKG_VERSION:=1.1.1
 PKG_RELEASE:=1
 
 PKG_BUILD_DIR := $(BUILD_DIR)/$(PKG_NAME)
diff --git a/package/qos-scripts/files/etc/config/qos b/package/qos-scripts/files/etc/config/qos
index 7d3501cc6edc208dc8b166aefc6b887e85b826fe..51959b5304d7573b4aa286794d36940376bf44ea 100644
--- a/package/qos-scripts/files/etc/config/qos
+++ b/package/qos-scripts/files/etc/config/qos
@@ -4,6 +4,7 @@
 config interface wan
 	option classgroup  "Default"
 	option enabled      1
+	option overhead     1
 	option upload       128
 	option download     1024
 
diff --git a/package/qos-scripts/files/usr/lib/qos/generate.sh b/package/qos-scripts/files/usr/lib/qos/generate.sh
index aceba577d58d3f4e35f30aa7748fb4b29855128c..a3c9f175c94eb2060c3f40ef2fdd4f76d9249895 100755
--- a/package/qos-scripts/files/usr/lib/qos/generate.sh
+++ b/package/qos-scripts/files/usr/lib/qos/generate.sh
@@ -14,6 +14,7 @@ add_insmod() {
 	# only try to parse network config on openwrt
 
 	find_ifname() {(
+		reset_cb
 		include /lib/network
 		scan_interfaces
 		config_get "$1" ifname
@@ -162,18 +163,18 @@ config_cb() {
 	config_get TYPE "$CONFIG_SECTION" TYPE
 	case "$TYPE" in
 		interface)
-			config_get enabled "$CONFIG_SECTION" enabled
-			config_get download "$CONFIG_SECTION" download
+			config_get_bool enabled "$CONFIG_SECTION" enabled 1
+			[ 1 -eq "$enabled" ] || return 0
 			config_get classgroup "$CONFIG_SECTION" classgroup
 			config_set "$CONFIG_SECTION" imqdev "$C"
-			[ -z "$enabled" -o "$(($enabled))" -eq 0 ] || {
-				C=$(($C+1))
-				INTERFACES="$INTERFACES $CONFIG_SECTION"
-				config_set "$classgroup" enabled 1
-			}
+			C=$(($C+1))
+			append INTERFACES "$CONFIG_SECTION"
+			config_set "$classgroup" enabled 1
 			config_get device "$CONFIG_SECTION" device
-			[ -z "$device" ] && device="$(find_ifname ${CONFIG_SECTION})"
-			config_set "$CONFIG_SECTION" device "${device:-eth0}"
+			[ -z "$device" ] && {
+				device="$(find_ifname ${CONFIG_SECTION})"
+				config_set "$CONFIG_SECTION" device "${device:-eth0}"
+			}
 		;;
 		classgroup) append CG "$CONFIG_SECTION";;
 		classify|default|reclassify)
@@ -231,19 +232,23 @@ start_interface() {
 	local iface="$1"
 	local num_imq="$2"
 	config_get device "$iface" device
-	config_get enabled "$iface" enabled
-	[ -z "$device" -o -z "$enabled" ] && exit
+	config_get_bool enabled "$iface" enabled 1
+	[ -z "$device" -o 1 -ne "$enabled" ] && {
+		echo "Interface '$iface' not found or disabled."
+		return 1 
+	}
 	config_get upload "$iface" upload
 	config_get halfduplex "$iface" halfduplex
 	config_get download "$iface" download
 	config_get classgroup "$iface" classgroup
+	config_get_bool overhead "$iface" overhead 0
 	
 	download="${download:-${halfduplex:+$upload}}"
 	enum_classes "$classgroup"
 	for dir in up${halfduplex} ${download:+down}; do
 		case "$dir" in
 			up)
-				upload=$(($upload * 98 / 100 - (32 * 128 / $upload)))
+				[ "$overhead" = 1 ] && upload=$(($upload * 98 / 100 - (32 * 128 / $upload)))
 				dev="$device"
 				rate="$upload"
 				dl_mode=""
@@ -252,7 +257,7 @@ start_interface() {
 			down)
 				add_insmod imq numdevs="$num_imq"
 				config_get imqdev "$iface" imqdev
-				download=$(($download * 98 / 100 - (100 * 1024 / $download)))
+				[ "$overhead" = 1 ] && download=$(($download * 98 / 100 - (80 * 1024 / $download)))
 				dev="imq$imqdev"
 				rate="$download"
 				dl_mode=1