
I think you should add an option on the Output section of the 3D Print Dialog. The Output section should include ALL the possibilities for outputting. It just is not clear that by DE-selecting the "Send to 3D Print Utility" option it will instead get saved to a file, such save file dialog popping up only after you hit OK.
So, instead of a checkbox on the "Send" option it should be a radio button and there should be AT LEAST a "Save to File" radio button option and maybe even a "Send To 3D Printer" radio button if Fusion 360 can detect that there's a 3D printer connected to the computer.