The Bach 461, comments on the ruling of the Tur that - Matza is adequately baked when there are no Chutin NimShaChim, no doughy threads stretching between the torn pieces of the Matza.
Following this straightforward guideline the Tur adds the unnecessary comment - but one does NOT fulfill their obligation if it is less well baked.
Analysing this redundancy, the Bach concludes that the Tur means to say that the worst outcome of dough baked below the thresh-hold of no Chutin Nimshochim, is that it is not Matza and one can not use it to fulfill ones obligation to eat Matza. However, one may eat it since it is not Chamets.
The Noda BiYeHuda derives the same conclusion from Rashi of Menachos 78b.
This means that although the measure of baking to convert dough into Matza is the point at which there are no Chutin NimShaChim, no doughy threads stretching between the torn pieces of the Matza, nevertheless the dough that is not yet at that point has still been sufficiently heated, when baked to a third or half way point, that it will not become Chamets. This third or halfway point is known as MaAchal ben-DeruSai (the food or eating of ben-DeruSai), so named after an infamous bandit who did not have time to eat fully cooked food. It is a well known measure used to define cooking for the Laws of Shabbat.
It is noteworthy that the Beit Yosef, in his compilation of the Shulchan Aruch, omits this redundant phrase, suggesting that there is only one critical point to be considered, at which the dough simultaneously becomes Matza and ceases from ever being at risk of becoming Chamets.
The Bach however, suggests that this matter is a dispute between the Tur and the Mordechai, the latter citing Rabbenu Shemuel from Perlayza - that Matza must be baked BeTuv and (as explained by the RaShaL, brought by the BigDey Yesha) is not to be removed from and then returned to, the oven. If the Matza removed from the oven still has Chutin Nimshochim, then it must be immediately incinerated in order to avoid any risk of possessing Chamets during Pesach. The not fully baked Matza (which in those days was baked during the Chag) that is removed from the oven must be destroyed immediately since it may be Chamets.
Now, according to the Tur (as understood by the Bach) the under-baked dough removed from the oven need not be incinerated. Although it is not yet Matza however it is far from being Chamets. It has irreversibly ceased to be Chamets from the moment it is baked to the point of MaAchel ben-DeRuSai.
In view of this argument, we should presume that the Beit Yosef chose to omit these redundant words and is therefore of the opinion that the Halacha is not as the Bach explains. The BYosef considers that the point at which dough is deemed to be baked is the same point at which it will no longer become Chamets, that is the point when there are no Chutim NimShoChim.
The Noda BiYeHuda (OCh2; 80) suggests that the dough may be baked fit to be a Matza but possibly only for a very short time as it emerges from the oven. He wonders, and cites another scholar of similar disposition, if it is possible that this Matza which has no Chutim NimShoChim might yet become Chamets.
It would seem that the Noda BiYeHuda did not have access to the Ritva who plainly (Pesachim 37) states that no such thing is possible.