Can't find the answer - Is it possible to render the attached proxie on export media?

I searched everywhere, but I can't find a way to render my timeline to my export output by using proxies.  Note that I don't want to create proxies, I want to use the proxies I already created as a source for render.

This is in order to save rendering time to pitch progress to my client.  I have already proxies attached to my master files, but I need to send iterations progress and quality is not required, only speed is important here.  I thought that keeping the toggle button for proxies will take care of that but I didn't see a difference in the render time, so I don't know if the renderer used the proxies to make the final output.

Any thought?