Are deductibles generally charged per visit or per procedure?

A little confusing so I’ll try to add some context. I have Meritain (owned by Aetna) through my husband and his work. We have a $500 deductible, a $3,000 individual/$6,000 family out-of-pocket limit, and a $400 outpatient surgery copay that covers facilities fees and additional physician fees. We also have the same exact plan as we had last year. All last year I was having severe abdominal and pelvic pain, and my doctor couldn’t figure out why. After a bunch of tests, we decided that an exploratory laparoscopy was the best option to figure out what was going on, especially because the working theory was that I had endometriosis. So in December 2025 I had my procedure and paid my bill ahead of time. It was $900 out-of-pocket: $500 for the deductible and $400 for the outpatient copay. During the laparoscopy, she discovered that I had a massive paratubal cyst that was torsed, so she removed it right then and there, and that was that. About two months later (now February 2026), I received an additional bill from the hospital for the actual removal of the cyst. It obviously wasn’t on the first bill, because we didn’t know that it would be needed at the time. I understand the hospital charging for it, but what I don’t understand is why I’m being charged an additional $500. The hospital said that it’s my deductible, so that’s what I owe, but do I actually have to pay an additional deductible when this procedure took place during the same visit at virtually the same time as the laparoscopy? (I also double-checked, and this bill is dated correctly and is listed as the same date as the laparoscopy.) I’ve looked through my plan documents and tried to understand them to the best of my ability, but they’re so confusing that I’m not sure if I’m reading them correctly, and some insight would be extremely helpful!