I made two different purchases/transactions on the same self checkout machine, one right after the other, at a local Walmart. One coded as "wal-mart XXXX" where XXX is the store number and got 5x, but the other coded as "WM supercenter XXXX" where XXXX is the SAME store number and that only gave 1x credit! The receipts show only about 1.5 minutes apart. This is frustrating...