First talks with home fertilizer manufacturers - tips?

Then the seller spends weeks crafting our individual construction service description and in the end (if the process should be different than described above), the architect throws 30% of it out the window again and the seller says annoyed "Why didn’t you mention this earlier?". In principle, he would be right.

The seller is not yet creating a more individualized scope of work description than referring to the offer on wall construction X or Y. The qualification you "demand" as a layman to interpret the development plan is close to zero. Reläääx.