A consultation model is not a rigid script - it is an internal guide that gives you structure. Without structure, consultations become disorganised, you miss information, you run out of time, and you score poorly.
The RCGP explicitly references consultation models in its feedback statements. Examiners may comment that a consultation appeared "chaotic" or that the candidate should "consider the various GP consultation models such as Neighbour, Pendleton, or Calgary-Cambridge."
You do not need to follow one model rigidly. The best approach is to read them all, take the best elements from each, and develop your own hybrid model that feels natural.