Well. for a start how about setting a limit that is still legal despite the chrono's inherent variability? Or at least recognising the need to allow the tolerance.
And how about a regime that doesn't involve disqualifying someone, just building up penalty points or warnings etc. When the present rules first came out it was even worse, one shot only on the chrono and if it fails you go home. i can recall RM announcing that at Curridge.
There are lots of things that can be done apart from spending thousands on a lab quality machine or dropping testing altogether.