Board Thread:The Panopticon/@comment-2162194-20170408131648/@comment-26845762-20170408143144

I believe this difference exists just because editors don't care about Ace as much as they care about the Doctor. : (

About half a year ago, Theory:Timeline - Seventh Doctor was made what it is today. The reasoning behind putting the Hex stuff after the NAs was actually almost completely related to Ace. Basically, Ace in the audios developed to be more mature than Ace when she first left the Doctor on Heaven. Instead of forcing us to go down the "according to one account" path, one can point to The Prisoner's Dilemma (audio story) as an explanation as to why Ace acts so young in early Hex stories: it's a post-NA story which has Ace lose many of her memories.

I'm sure they explain it better on the timeline page.