The linked reference refers to a concept of time, where incrementally means a progression of monotonically increasing units from a specific point.
I see how this could be misinterpreted as describing a monotonic clock. But it only describes properties of the timeline.
That document does not even talk about specific clock sources, which is more of an implementation detail compared to the discussed user facing concepts.
It’s an unfortunate reality that terms related to time keeping are not always precisely defined. There is serious and confusing term overloading 
We noticed that very drastically while discussing RFC 15 that sometimes different sources apply entirely opposite semantics.
Perhaps we need to find a better definition to link to, or write our own glossary for time related terms 
(RFC 15 already has a starter)