My airline uses the dismissal of the ground engineer after start as dispatch. Having tried a few different methods, i find this one excellent and logical. Obviously prior to dismissal of eng, you can still consult about problems, after that you are on your own. From that point until take off, the MEL is advisory only.i.e Captains discretion. So if the problem will be limiting down route, he has the option to come back to the gate, if it is not limiting he can continue as per the non-normals.
Copulater
The Rev