Yes.
There are always requests and negotiations in play. But those three channels sufficed almost all the time. At times we'd combine channels if there was an urgent need and agreement from customers.
The slowest customers were the most enterprise-y. Things almost couldn't go slow enough for them. When there were complications to the release process, they could be a release version or two behind and there'd be a catch-up release.
We also had customers outside all of this, and had custom releases, and we charged very high fees for this. Ultimately, we were able to bring them back into the slow release because the extra work wasn't really worth it. Part of the requirement for these kind of customers is to have additional engagement efforts to make sure their internal teams were really aware of the details and contingencies of releases. Big companies move slow and need over-communication, and you can't trust them to do it themselves. It was more effective to take that responsibility on ourselves.
I preferred to take the things that were difficult and do them more often. Keeping a cadence to things kept everyone together. The minute you break cadence -- and entertain special circumstances -- it's really hard to get back on cadence, and that cadence includes testing, notifications, documentation, feedback, approvals, releases.