diff --git a/src/Handler/SAP.hs b/src/Handler/SAP.hs
index 10b71fd9f..34b00b81b 100644
--- a/src/Handler/SAP.hs
+++ b/src/Handler/SAP.hs
@@ -79,13 +79,13 @@ compileBlocks :: Day -> Day -> [(Day,Bool)] -> [(Day, Day)]
 compileBlocks dStart dEnd = go (dStart, True) 
   where 
     go :: (Day,Bool) -> [(Day,Bool)] -> [(Day, Day)]
-    go (d,s) ((d1,s1):r1@((d2,_s2):_r2))
-      | d1 == d2 || succ d1 == d2 || s == s1 || d1 < d = go (d,s) r1  -- ignore unnecessary change
-    go (d,s) ((d1,s1):r1)
-      | s, not s1
-      , d < d1, d1 < dEnd = (d,d1) : go (d1,s1) r1                    -- valid interval found
-      | s == s1           =          go (d ,s ) r1                    -- no change
-      | otherwise         =          go (d1,s1) r1                    -- ignore invalid interval
+    go b@(d,s) ((d1,s1):r1@((d2,_s2):_r2))
+      | d1 == d2 || succ d1 == d2 || s == s1 || d1 < d = go b r1  -- ignore unnecessary change
+    go b@(d,s) ((d1,s1):r1)
+      | d1 >= dEnd        = go b []                               -- remaining days extend validity
+      | s, not s1, d < d1 = (d,d1) : go (d1,s1) r1                -- valid interval found
+      | s == s1           =          go  b      r1                -- no change
+      | otherwise         =          go (d1,s1) r1                -- ignore invalid interval
     go (d,s) []
       | s         = [(d,dEnd)]
       | otherwise = []