Personally i use ×-1 for refund as it then makes order tags negatove also as if your refunding the tag value should be refunded too.
However if you dint want the tags dont add them surely. I though refund typically is applyed tk new orders. You woildnt refund an order already submitted and sent to kitchen as they would then not knly get the item but get refuns for something not paid for. Or if it was a closed/paid bill you wouldnt want to refund as then you nlt only eemove the origiknal sale value but then refund it too so what was a sale for 10 goes to refund of -10 ie difference of 20.
Usually redund you should leave the origiknal order (10) and put a refund though for -10 cancelling out to 0.