修复账单缴费余额与结算余额错误

application/em/model/EmInvoice.php

@@ -49,7 +49,7 @@ class EmInvoice extends Base
              if(number_format($item['settle_balance']) == 0){
                  $item['sett_amount'] = 0 ;
              } else {
-                 $item['sett_amount'] = number_format($item['settle_amount']) - ($item['settle_balance']);
+                 $item['sett_amount'] = number_format($item['settle_amount']) - number_format($item['settle_balance']);
              }
         }
         return $data;