I get that SKU is different from barcode. Which is better. I'm a small business with much varied product. I don't have much time before I open shop. I still must create and update inventory. Don't I need to add the SKU or Barcode at the same time when I upload? I'd rather figure this out now than at the very last minute. I have a Clover Flex. I did not buy the accompanying bar code printer. I plan to use my current office printer with Avery labels. Any advice will help. TIA