diff --git a/xorriso-dd-target/xorriso-dd-target b/xorriso-dd-target/xorriso-dd-target
index d378e017..7edf05a8 100755
--- a/xorriso-dd-target/xorriso-dd-target
+++ b/xorriso-dd-target/xorriso-dd-target
@@ -117,8 +117,18 @@ print_usage() {
 
 # Roughly convert human readable sizes and plain numbers to 1 / million
 round_down_div_million() {
-  sed -e 's/\.[0-9]*//' -e 's/[0-9][0-9][0-9][0-9][0-9][0-9]$//' \
-      -e 's/[Mm]//' -e 's/[Gg]/000/' -e 's/[Tt]/000000/'
+  sed \
+    -e 's/^[0-9][0-9][0-9][0-9][0-9][0-9]$/0/' \
+    -e 's/^[0-9][0-9][0-9][0-9][0-9]$/0/' \
+    -e 's/^[0-9][0-9][0-9][0-9]$/0/' \
+    -e 's/^[0-9][0-9][0-9]$/0/' \
+    -e 's/^[0-9][0-9]$/0/' \
+    -e 's/^[0-9]$/0/' \
+    -e 's/\.[0-9]*//' \
+    -e 's/[0-9][0-9][0-9][0-9][0-9][0-9]$//' \
+    -e 's/[Mm]$//' \
+    -e 's/[Gg]$/000/' \
+    -e 's/[Tt]$/000000/' 
 }
 
 ### Assessing arguments and setting up the job