Experience with 50% renovation clause?

I subbmitted a plan for a major remodel (2nd story) and I didn't realise there was a 50% renovation clause burried at end of city zoning.
Basically if your proposed project value is 50% or more compared to existing structure value then they want everything brought up to code.
So I either shrink my plan to get under this 50% level or I go ahead and have this open-ended question of how much re-building the BO will be happy with. If it is just insullation and wiring that would be fine but if he wants he could require testing of concrete footing and bla de bla ---list goes on forever.
Since he has made it clear that he "aint gonna help me at all no way" then what can I do?
If I shrink the plan how do I know how far to shrink it? For instance - if I save my existing 2x8 floor system and add to it front and back how much is considered brand new construction? If I leave the floor but want new walls & ceiling is that 33-1/3% ?
I don't see how anyone but city can clearly define this but since they re-fuse to help all I can do is keep subbmitting plan changes until they say OK- we agree this is 49%.
Any one else been thru this rediculous game?
Like the bldg code isn't complicated enough without this stuff!

You're dealing with big city politics and over-government there.. Some local ordinances are so over the top that they discourage development and encourage abandonment and decline of neighborhoods.

I do not envy your situation at all. Dealing with strict local building codes and enforcement has brought contractors to their knees before. I suppose the ordinances are there for a reason, brought on by past experiences, but if they have brought remodeling to such a standard that you can't get approved.. Then they have surely stopped development for others also. Electrical, Plumbing, Heat and Air, Insulation and Building Material Standards are important. But if a structure has stood for 50 years as is, it must not be too bad

It sounds to me like the city wants to keep fly-by-night crews out and wants to control fire and health hazards. You need to find a contractor who has dealt with them before and ask him how far the city went to inspect and what demands they made on him. Doubling the size of a home will surely place a larger demand on the electrical system, the plumbing and the heat and air. Consider the added weight on the exterior walls and check the width of your foundation walls. The code is there for a reason, make sure your existing structure is up to par before you invest your money in a project that will never pay for itself after the city is done with you.

Only a local who has been through your situation can help you.

Welcome to the forum!