Yup, this is what I've seen. Changes tend to come in three types
a) Routine: A known change that occurs regularly and doesn't deviate much from a standard pattern. Stuff like swapping tapes, etc. It still gets logged and can be reviewed, but doesn't need approval.
b) Standard: Goes through an approval process before being implemented. These are basically known changes that can be planned ahead of time, but they don't necessarily have a standard set of steps
c) Emergency: Basically a form of (b) that needs to get done FAST. They can be reviewed by the CAB, but don't go through the normal approval process (they may need sign-off from one uber-admin, or none depending). This is intended for stuff that can't be pre-planned and is high-impact/danger if left unhandled. For example, patching may be a standard thing, but patching openSSL due to heartbleed would probably have been an emergency in many cases.