In our family, there was a similar case recently, also Saarland. There, UBA said the deadline only starts from the point when the building application is complete. Unfortunately, they only received the letter that something was missing 6 weeks after submitting the application. So those 6 weeks just passed without any benefit. And it was also said that the time until the municipality decides does not count towards the 3 months. The whole thing had to go to the building committee twice and once to the municipal council, of course that took some time again. To what extent this is comparable to your case, I do not know. That’s why I wrote it in the subjunctive. You should check your state building regulations, it will be stated exactly there. A few meters further in RLP it is different again, and with our first house in Bavaria it was different once more. This is just incredibly annoying and you don’t make progress and depending on who you deal with, they will exploit it as much as they can if they feel pressured.