Wait, proximity sensors show the distance in meters of the device tracker or person from a zone and recalculate anytime that device tracker or person does right? On a decent length drive I would expect hat to update as frequently as your phone reports in. And it doesnt look like you have a time throttle on there so are you sure it’s not polling too frequently?
You might want to consider adding a condition like one of the ones I showed here to add a time throttle and ensure it’s never able to run too frequently. Even if one of those devices starts reporting in faster then expected for some reason.