So I sell greetings cards in the UK with two options - send to me, send to someone else. When a customer clicks the send to me option, the item is bigger due to larger envelope its shipped in. I reflected this in my shipping by adding two separate custom shipping rated based on weight. I also entered the envelopes weight into the packaging section. My rates are based on Royal Mails weight allowances for large letters. Setting the shipping calculation based on weight did not work, so I tried it with price (since all my items are the same price). An example is 3 cards should weigh 258g (or £10.50 in order price) which would make the postage £1.49. But when I go to checkout it shows the postage price for 1 card. I dont understand why the custom shipping rate isnt working.