No, not at all! Just that practice makes perfect.
He’s used to his own way of masturbating so he’s probably used to a hard and fast jerk off to the finish line (he should take it easy with that!).
So maybe you just haven’t been able to get the pace he needs at the end. Ask him! Try speeding up, sucking harder, etc. See what works. You can’t do the same thing every time and expect different results. Think of it as a fun experiment, not something to stress and worry about. It’s all about getting to know each other and what each of you like!
It’s helpful to combine your hands and your mouth when giving a bj. The two different tactile sensations are awesome! (Ie. one hand on the base of his shaft, jerking him off, covering whatever you can’t fit in your mouth.)