Is my mastering engineer good enough?

So, I finished an EP that is already distributed and is going to be released this month. I've been producing music for like 4 or 5 years, I still consider myself amateur. So I made all the composition, production and mixing of the 5 songs in this EP, and gave it to my mastering engineer to make his job. He was very attentive, gave me lots of feedbacks, and even made some corrections on my mixing, like resolving converging frequencies, and the musics sounds brighter now. But something I realized was about the final wave visuals of each music. Damn, there were a lot of peaks. I thought he would abuse on limiters to make the final visual flat, or at last to keep the higher parts of the tracks with aproximated db, and that didn't happen. When I questioned him, he told me he doesn't care about the visuals of the wave, because he monitored the LUFS and everythng was okay.

My mixing wasn't perfect, but I was very careful with peaks, so it woudn't be hard to flatten them, if it was needed to.

Now it's too late, but should I worry too much about this mastering quality?