The key phrase comes at the end of the CNN outline:

“We have discussed these changes with the Republican National Committee […] and they are fully supportive.”

The RNC/GOPe has a transparent vested interest in getting any of the “splitters” onto the primary debate stage.  At this point, the goal has modified from simply reducing the “non-jeb” vote, to a more immediate need of reducing the Donald Trump vote.
(Via Politico)  CNN announced on Tuesday that it has changed the criteria for its upcoming debate, making space for Republican presidential candidate Carly Fiorina on the primetime stage.
Fiorina had argued for weeks that CNN’s debate criteria unfairly weighted early field leaders over contenders like her who have polled better since the Fox News debate on Aug. 6.
According to CNN, any candidate who ranks in the top 10 between Aug. 6 and Sept. 10 will be included in the primetime debate on Sept. 16. Also allowed in the main show will be candidates who scored in the top 10 averages of all approved national polls between July 16 and Sept. 10, as the original criteria released in May stated. This means it is possible there will be more than 10 candidates on the prime time debate stage.
The new approach allows the network to avoid looking like it’s favoring Fiorina at the expense of candidates such as Chris Christie and Rand Paul who would have been at risk of getting bumped to the earlier debate if CNN had more heavily weighted later polls, as Fiorina had suggested.
Still, CNN warned in an announcement that final podium placements won’t be known until Sept. 10, after all national polls have come in.

“In the event that any candidate is polling in the top 10 in an average of approved national polls released between August 7th and September 10th, we will add those candidates to our top tier debate, even if those candidates did not poll in the top 10 in an average of approved national polls between July 16th and September 10th. We have discussed these changes with the Republican National Committee and the Ronald Reagan Presidential Library, and they are fully supportive.”  (link)