In "The Time Monster" the Doctor claims that the TARDIS's mood determines how long a journey takes through the Vortex.
While the EU says that travel time is effected by the efficiency of the space-time course within the Vortex, and TARDIS power levels, it also states that there's very little relation between Normal Space distance and the perceived travel time in the Vortex. And there's nothing in the EU to contradict the idea that TARDIS mood also has a major effect.
Given all this, I was expect a random ETA table much like FASA's RPG rules had, but the TTC actually gives speeds for the TARDIS's travels based on normal space distances. This seems at odds with all of the above info. Was there information from another TV episode that contradicted "The Time Monster"?
In the Time Monster though, they're travelling primarily backwards in time, and not that far in space (back to Atlantis) - possibly the TTC is mostly concerned with traveling in space, rather than in time?
Of course the other possibility was the Doctor was blaming the TARDIS for his own lack of skill with using it