diff --git a/src/lib/ContractMessages.fif b/src/lib/ContractMessages.fif
index 505a8f8..59cb827 100644
--- a/src/lib/ContractMessages.fif
+++ b/src/lib/ContractMessages.fif
@@ -75,7 +75,13 @@ b>
 
 { 1 3 -roll <b b> mkRawReqMsg } : mkJoinMsgBody
 // ( sk pkn wc addr -- cell )
-{ 2 6 -roll <b 3 roll 121 i, -rot { ref, } if b> mkRawReqMsg } : mkCloseMsgBody
-// ( sk pkn wc addr payout miou bool -- cell )
+
+{ 2
+  over { 6 } { 5 } cond -roll
+  <b -rot { ref, swap } if 121 i, b>
+  mkRawReqMsg
+} : mkCloseMsgBody
+// ( sk pkn wc addr payout (iou true | false) -- cell )
+
 { 3 3 -roll <b b> mkRawReqMsg } : mkTimeoutMsgBody
 // ( sk pkn wc addr -- cell )