Let me be the first to welcome you to the Community forum, @KristinMT.
I appreciate all the details you provided regarding what you need to achieve for your total estimate. At this time, you can only bill the purchase of equipment using the estimated amount.
This kind of feature wherein you calculate the purchase when adding to an invoice is currently unavailable. The invoice will only show the quantity rate and amount and not the percentage of the purchase. You may add a description to view the details on how it was calculated.
I'll pass along feedback and let our developers know about this. In the meantime, you can visit our Product Updates site if you want to keep track of what's new with our products and services.
Please tap the Reply button if you have follow-up questions. I'll be here to help however I can. Have a good one.
