Edited to remove some baseless speculation.
Given how the screen refresh routine works, I don't anticipate an increase in processor overhead to show a live state screen. It will likely be less taxing than the tracker display. There will be more code, certainly, but it will only be called in exclusion to all other display refresh branches, e.g.: the tracker display code will not be run when the live state display code runs.
TL;DR: I don't think that adding some code to the screen refresh routine will tax the processor.