Thw problem is your interpretation of adjust.
The word adjust simply means that one must change his or her current existence to match the needed existence.
As a result, adjust can mean almost anything. Decrease his power, increase bis power, change the shape of his chakra, change the density (how tightly packed) of his chakra.
You see adjust and instantly assume it means that he has to hold back, when any of these options are possibilities
As for Obito vs Sasuke...that ended two chapters ago when they got face palmed by a semi-concious Obito. Before you argue it is because he had to save Naruto, you are wrong. He clearly was standing there,, Obito also not moving, and had.time to spout some arrogant boasting before realizing Obito was moving in for an epic hand to face encounter.
Obito is literally too OP with his automatic damage tanking, speed, and semi-liquidous Jinton.