My experience was similar at a medium size business. We had reusable keys that we used as needed. Once a year, we would run their audit tool and pay the difference.
I never got the impression they cared where the keys came from. We knew exactly when they were coming every year. They were easy to deal with and I don’t recall ever having any issues.
We also had an ELA with VMware and they were awful. We only stuck with them because the software fulfilled a need. They treat you like dirt during the sale and every renewal. In between, they act as if they’re the ones doing you a favor by allowing you to be a customer. The support was terrible.
But oddly enough, they always gave us more licenses than we paid for. Every time, they would throw in products we didn’t purchase and weren’t cheap about it either. It was always like 100+ seats and one time it was 1000.