I was referring to the fact that the lawyer would preferably not hold the OP liable for a denied building permit; logically, this logic would then also have to be applied to the surveyor's service.
Without having read everything in detail, I also consider 29 pages of changes to be excessive, unless the contract actually has such extensive defects that justify it. However, some of what the lawyer writes does not, in my opinion, correspond to building regulations law, because the builder does not get completely released from liability there for good reason – especially not on their own property.
The lawyer naturally tries to minimize or even eliminate all risks for the builder; whether she actually succeeds is another matter, because I will now claim from my well-founded layman’s opinion (note, this is not legal advice!) that the building application cannot be formulated as a contract for work. This may work in 99.9% of cases in practice because there are no insurmountable obstacles, but occasionally there is no building permit (e.g. contamination, neighbor sues against construction and/or zoning plan and wins, zoning plan unlawful, access path not secured, city exercises pre-emption right, etc. pp.) – and how is the general contractor supposed to remedy this as part of a contract for work? Some things can be solved with time and money, but some simply do not work because the legal issues cannot be resolved.
And then, in case of doubt, the question is who will pay for the effort up to that point. As a contractor (surveyor) you may be left with the costs if you cannot prove who gave the order and when. Some things are arranged by phone, which is problematic if damage occurs – also for the builder or general contractor.
And to bring the subject back to the core question: in my opinion, the planners/general contractors take a big risk with their statements/promises regarding the trade "building application," because below about €1 million construction cost (which is understandable because the builders do not pay/tolerate it) little to no effort is made to assess the risk of a building permit not being granted. The building application is simply submitted and possibly corrected afterwards. This also explains the 10%; for some large special projects, the building application could be set at +25%, because the building permit is a major, if not the greatest hurdle.
So what happens: with a house value of €250,000, the disputable amount is 10% = €25,000; this halves because one is likely to settle regardless of how the lawyer formulates it, so statistically €12,500 is lost by the general contractor, from which the rest must/can pay the effort – including the surveyor! – of a construction project (trade) that ultimately does not lead to a building permit.
However, if he does not take the risk "building application," his business model is broken.
Best regards
Dirk Grafe