diff --git a/mandel.s b/mandel.s
index 6be37d2..210799a 100644
--- a/mandel.s
+++ b/mandel.s
@@ -1737,12 +1737,15 @@ update_status:
 
 skipped:
 
+    ; sx += fill_level[fill_masks] + 1
+    ldx fill_level
+    lda fill_masks,x
     clc
-    lda sx
-    adc #1
+    adc #1 ; will never carry
+    adc sx
     sta sx
-    lda sx + 1
-    adc #0
+    lda #0
+    adc sx + 1
     sta sx + 1
 
     lda sx
@@ -1752,12 +1755,15 @@ skipped:
 
 loop_sx_done:
 
+    ; sy += fill_level[fill_masks] + 1
+    ldx fill_level
+    lda fill_masks,x
     clc
-    lda sy
-    adc #1
+    adc #1 ; will never carry
+    adc sy
     sta sy
-    lda sy + 1
-    adc #0
+    lda #0
+    adc sy + 1
     sta sy + 1
 
     lda sy