I get data which looks like the following:

VOUCHER #  INV_AMT  DST_AMT
76171      606.20   606.20
76172      301.87   501.87
76173      667.75   675.50
77093      706.14   706.14

I don't understand why the 1st and 4th records appear in the results. Does anyone understand why this happens based on the following code?

SELECT ;
		APTRXFIL.VOUCHER_NO, ;
		APTRXFIL.INV_AMT, ;
		SUM(APTRXDST.DST_AMT) AS DST_AMT ;
	FROM ;
		APTRXFIL, ;
		APTRXDST ;
	WHERE ;
		APTRXFIL.VOUCHER_NO = APTRXDST.VOUCHER_NO AND;
		APTRXFIL.INV_AMT <> SUM(APTRXDST.DST_AMT) ;
	GROUP BY ;
		APTRXFIL.VOUCHER_NO, ;
		APTRXFIL.INV_AMT ;
	INTO CURSOR tmpAPTransactions