I'm glad you found this interesting! I wonder if the differing approaches to the Pertwee era stem from Miles and Wood's very different opinions about some aspects of Doctor Who. In some places in the About Time series they are quite explicit that they disagree, but in other places what comes across as a unified editorial voice turns out actually to be one or other of them saying individual. Certainly they seem to have fallen out in the course of writing these reference works and Miles, at least, occasionally says quite biting things about Tat Wood on his own blog (in posts he has a habit of subsequently deleting). It's possible the problems I had in some places with About Time 2 were a result of the cracks beginning to show.

parrot_knight is far more of a media and specifically Doctor Who historian than I would ever claim to be. I don't think I ever spotted errors in the About Time books, but they don't fall into my field of expertise at all, except as a hobby and I've certainly heard them criticized in several places for not being as accurate as they make themselves out to be.

EDIT: In fact I note both parrot_knight and daniel_saunders have discussed the inaccuracies in the books and the uneven editorial voice in previous comments to this entry...