Tell me where we can find the development plan (links are not desired here, so better in the format "Posemuckel No. 258 in Wiesengrund" or something - you have a PM). With such an atypical roof, I strongly suspect that there are regulations that inspire the architect to such an extraordinary idea.
In the floor plan, I didn’t even notice the "dormers" at first, nor the knee wall. It is indeed a knee wall, and also according to my interpretation it would be 75 cm (as numerous development plans imagine it if the house is supposed to be "Franconian"). And normally I say that this knee wall height is rubbish because I expect a knee wall to fully substitute a dwarf wall; and I also see the most practical knee wall heights to be in the range between 100 and 130 cm (namely the bed knee wall). Then you can put facade windows in the knee wall and roof windows in the roof slope.
But here it is quite different: one is content with the 75 cm "vacuum cleaner knee wall," constructively clean up to this point without doubling the knee wall with a dwarf wall - but then comes the catch: the roof is "pulled in front of" the roof projections, which together with the low knee wall prevents reasonable facade windows from being placed in the knee wall. Instead - and this is where I say no capable architect would do this without reason - dormers are set on the knee wall. You’ve really fooled me here, because without the section drawing I would almost have been tricked into seeing "dormers" just from the elevation. But here they are dormers with a shed roof - hardly more atypical, and basically you don’t do such a thing without reason. In this respect, one would actually have to assume that classic dormers (with gable, then actually "returns") would be excluded here not only for cost reasons but also because of a reason coming from the development plan. However, you are right about the bat dormer; that would clearly exceed the shown solution financially and in terms of effort (but would be rather northern German).
Has a carpenter already given his opinion on how complex he considers this roof construction? - after all, the windows can apparently be made without changing the rafter spacing; however, that also gives the house a strong 1950s neighborhood house flair. From the outside alone, I would not classify the finished house as a new build but as a renovation object with a modern front door.