While doing as proposed would not have any negative effect on the vehicle, I see doing so as a complete waste of time and resources. Why would you go around the whole car just to find out that the results do not meet your expectations when you're finished?
Many will recommend a test spot to dial-in your process before proceeding with the entire vehicle. If the test spots meet your expectations, then proceed. If not, alter your process as necessary until they do.
Personally, and typically, I don't do test spots as in the classic 2' by 2' section. What I do is make an assessment of what I think will be necessary, based on experience, to achieve the desired result and then get to it. I'll use my first section, and/or panel, as my test spot. I'll assess the results and make adjustments, if necessary, before proceeding with the entire vehicle.
If there are isolated areas/defects that require additional attention, I'll usually address them first before making my final passes over the entire section and/or panel.