Hello khalaur,
I love that you've discovered the flexibility of QuickBooks Desktop's template customization. Being able to add custom columns and fields is a great way to add your own personal touch and make sure your customers have all the information they need.
I can absolutely see how being able to link those additional columns with another section of data somewhere in your books to have it automatically populate information would cut down on the work you have to do. At this time, these additional fields cannot be mapped to pull data from elsewhere in the program. Manually entering the information is the way to go to make sure it's all in place.
I welcome you to submit feedback about this through the Help menu by choosing Send Feedback Online. We value our customers' thoughts on the program and love to hear the ways that we can enhance what it can do.
For your reference, here's our article about form templates in QuickBooks Desktop: Use and customize form templates
Let me know if you have more questions!
