No both of you are wrong and there no such thing as RM20 min redeemption or purchase and did UOB says so
Below are T&C from UOB Clause 8
8) No minimum purchase is required for Cardmembers to perform redemption of their SMART$:
a) If the value of the transaction is more or equal to the accumulated SMART$, the Cardmember may redeem the whole, but not part, of the accumulated SMART$ towards full or partial payment of the goods and/or services purchased from the SMART$ merchant. The value of the accumulated SMART$ shall be deducted
from the value of the transaction; the balance (if any) is payable by charging the same to the Cardmember’s Credit Card, and not by cash.
b) If the value of the transaction is less or equal to the accumulated SMART$, the Cardmember shall be entitled to redeem part of the accumulated SMART$ equivalent to the value of the transaction.
c) Purchase may not be made using a partial redemption of SMART$ and the balance by cash. UOBM will not accept any of such SMART$ adjustments or disputes from Cardmembers.
please let me know which bhp station which allow you to redeem any amount of smart$? i will check with them directly to double confirm it. bcs all the bhp which i been to across malaysia, all have this minimum rm20 thingy.