Poor controlling technique. Controllers should not try to fly the aeroplane......that's your job. Don't think I ever used that during a long career. Instruct or clear "level by" and let the pilot choose the solution..... would be my preference. Of course the real answer may be the particular traffic scenario at the time.......a friendly query letter to the ATC agency might explain.
In our sectors we are too busy for that. I don't have time to measure and calculate distances from waypoints as aircraft are never on standard routes.
'level by' is a waste of time and doesn't work when you must cross under 3-4 different flights at multiple flight levels.
I would suggest you let controllers answer the questions
