I am about 300 points higher and think this is roughly correct. In openings amateurs will actually analyze more since GMs just have hundreds of opening lines memorized many moves deep. Middlegame and endgame there're usually just 1-3 reasonable plans that are immediately obvious to a GM (but not at all obvious to amateurs) with 1-3 initial moves each. So, again, probably about as many as I consider.

The only time when GM will definitely analyze more lines than an amateur is in a highly tactical position but that happens, again, maybe 1-3 times per typical game (tactics themselves will last several moves, but they would be largely calculated through at the beginning of the tactical melee).