Yeah, that matches my experience pretty well. I tend to lift from published material and then expand and modify on my own prior to starting play, and then even more once play begins and the players start to dictate how things go.I have run adventure paths. I look at them as more like guidelines, as some have ended up very far off what was published, although, I could still mine enough information from the later parts that they didn't become useless. One time, in particular, the players were so surprised that the adventure they loved got poor reviews. Had to explain what they did wasn't that close to the official AP. This wasn't because I'm a brilliant adventure designer, bur because the players pursued their interests, and I moulded my GMing around their characters.
Other times, APs will run pretty much as written, not usually though.
But I have run some published adventures largely as presented and had it go quite well. I don't think there's anything inherently bad about any approach; it's more about expectations and experience being aligned.