At the end of the script add
DROP TABLE Table_1;
An implicit concatenation always happens in Qlik whenever two or more tables have the same number of fields and these fields are named alike.
EDIT: FWIW, You can save one LOAD step by doing
Table_1: LOAD [GROSS AMOUNT], [GROSS RECLAIM AMOUNT], [GROSS AMOUNT]*(ApplyMap('TableMapping',[ISO COUNTRY CODE] & [CATEGORY NAME],'missing')) as Multiplier FROM restricted;
You can use expressions as parameters for ApplyMap() as well instead of first generating the composite key and after applying it.