I see what you're saying. I've just checked with our engineers and this is the default setting in QBO. The program only allows you to use an imported template when creating a brand new invoice and not creating one from an estimate. I know how much this feature would help you save time. I encourage you to leave feedback for our engineers. You can do this by clicking the gear icon and looking for Feedback. New product ideas and improvements are largely based on the feedback we get from other users like you. Feel free to ask questions. :)