diff --git a/lib/bill-math.js b/lib/bill-math.js
index fa0b8db8..8f5daea5 100644
--- a/lib/bill-math.js
+++ b/lib/bill-math.js
@@ -138,7 +138,12 @@ const solutionToOriginalUnits = (solution, units) => {
 
   const billsLeft = _.flow(
     _.map(([denomination, provisioned]) => [BN(denomination), provisioned]),
-    _.fromPairs,
+    _.reduce((acc, value) => {
+        acc[value[0]] = (acc[value[0]] || BN(0)).plus(value[1])
+        return acc
+      },
+      {}
+    )
   )(solution)
 
   return _.map(