Yeah, I’m not sure it’s cheaper for medics (given the resource it cuts into). Though their big +++ is definitely the mastery damage reduction. Thanks for refreshing the memba berries though 
It happens all the time. And I think due to its movement speed increase, you can get that last unload (if not +2 extra, doubt it). I’ve never paid attention exactly. They have same speed as SCV though (just longer excavating time for bigger unload).