Is it normal to have teeth filed during cleaning?

I just went to the dentist for a cleaning. It was my second time at this office, the first a year ago. He had me bite on a paper type substance and grind my teeth. He then filed down parts and called it 調節. I had no idea what was happening until it was done and saw some of my teeth has been filed.

I don’t recall this ever happening before in my home country (USA) or a different dentist I’d visited a few times when I lived in another prefecture.

Is this normal??? I’m feeling a little violated at not knowing what was happening to me until it was done.

They want me to come back to put some fluoride on one part that looks like it could turn into a cavity and told me it’ll cost just under 10,000 yen and an hour to do it. That also seems very steep for Japan but idk. I’ve been blessed with healthy teeth until now…