POSTAL RATES TABLE ISSUE

[valley_pottery]

I NEED HELP!  No help from Eaby. I have been using the postage rates table as I add postage per location. The table option only appears when I select "flat rate for all buyers" in the Domestic Postage section which is strange but it should be should be "calculated". If I use "Calculated-Cost varies by Location" the option for rates table disappears.

My problem is that if I don't put an amount in the "flat rate" box the item comes up as "Free". That is until a customer enters their post code then the rates table is activated and shows the correct postage. If I do put an amount in the "flat rate" box the same problem happens - the buyer sees this flat rate postage until they enter their postcode and the rates table charge appears. This is causing me a lot of problems with customers. They are complaining that it shows Free Postage and then they go to buy up and the postage appears. I can not count the number of customers that have complained to me about it. I have tried all sorts of combinations but none work. I use Sendle and send out the same large 11kg size box every order. ANY IDEAS what I may be doing wrong???