Tool/program regarding a clear listing of construction costs

I have a small comment. You will not be able to specify some items exactly. If points are included in the [Bauleistungsbeschreibung], meaning they are part of the offer, you will hardly be able to say what they cost. It could also be rather difficult to break down the individual trades if you have a total offer from a [GU/GÜ].

I wouldn't enter a medium value, but rather a high value for individual items. For example, a basic appraisal can cost 700-1500, so set it at 1000 (ok, average). Flooring prices are always a bit higher per sqm with a 30% surcharge for adhesive etc. You can get rates by searching for Baunebenkosten; there are other items there, but not individual trades.