The interior painting template is distributed to accounts with 4 generic paints; Interior Primer, Interior Ceiling Paint, Interior Wall Paint and Interior Trim paint. More than likely a brand name paint is being used such as Benjamin Moore or Sherwin-Williams. If you use multiple paint brands you can easily add new paints to the existing template.
To add a Sherwin-Williams Duration wall paint that could be used instead of the generic wall paint for example navigate to Settings > Item List. Click on the Materials filter to show just materials and then search for interior wall paint. This will show the 3 paints included in the default interior item template.
Click the edit button next to Interior Wall Paint (gallon) and select the copy item option. This will copy all of the information from the existing item into the new item (for the sake of being consistent across material items) . Type in Sherwin-Williams Duration and edit any other details before clicking Save.
After saving the Sherwin-Williams paint you could then repeat the steps to create a material item for Benjamin Moore Regal Select for example and any other paint material that you are using.
Pros - Doing the copy step and adding multiple materials will make it easy to do bulk material substitutions later on your interior projects.