Even though the example is on a fixed dollar amount the whole passage ends with this:
What does your plan say?
Although not common, a plan can specifically require that salary deferrals cease once a participant’s compensation reaches the annual limit. If your plan specifies that salary deferrals be based on a participant’s first $250,000 compensation, then you must stop allowing Mary to make salary deferrals when her year-to-date compensation reaches $250,000, even though she hasn’t reached the annual $17,000 limit on salary deferrals, and must base the employer match on her actual deferrals
To me that makes it clear that in their (IRS') mind your plan has to specify that deferrals be based on the participant's first $250,000 compensation to get the result the auditors are talking about.
I am with Austin at this point enough evidence has been given to support the belief of the people on this board. It might not be enough for the people who are asking the question but that says more about them then the evidence.