Thanks for your message, I would be happy to help you out with this. In regards to, “shipping calculated at checkout”, you should be able to change this by editing your language settings in your admin. Head to, Online Store>Themes>Actions>Edit Languages in the “Filter Items” section you can search “Shipping Calculated at checkout” to find that specific text. Or, you can click the “Products” tab when in the languages section:
Usually, that shipping calculated message is filled out when you have text entered in the Shipping policy in settings > Legal.
In regards to:
“Ships from” tab on the product page
“Capacity” tab on the product page
Apologies, but I was not able to find these areas at your shop. Are you able to send a direct link to where these show up or share some screenshots so I can take a closer look?