Hi MCP User, thanks for sharing the link.
Do you mean variation listings? They supported by MCP, they automatically populate the relavent data into the variation section. You may have columns in that section hidden...
I assume you dont ship through the eBay shipping program which would automatically update MCP with the exact shipping cost, and I assume you mean changing the shipping cost on the Product Master tab... You can change it there; the updates will only affect new sales on download.
For the button click to apply to existing sales, it will only effect sales that have a blank value... in other words, if you already have a shipping price in the sold item tab, it will not overwrite it.
Lastly, MCP is a yearly subscription!
https://mycostpro.com/downloadIf you purchased it on eBay it is not setup for auto renew, but it is still only active for 1 year (365 days).
Scott