Whenever a client asks me to do something, I never confuse it as an order. I have never given them the power to do that. They don’t have keys to my office, or passwords to access my PC and signature.
It sounds like OP missed addressing the partially renovated bath in their original report, and at the clients suggestion they are now exploring how to do that with a cost to cure.
A cost-based adjustment is a valid adjustment in situations like this. Costs are market reactions. I don’t see how interviewing realtors or reconciling to the low end of the range is any more reliable than doing a cost analysis.
Costs are not always market reactions. If they were, then a flipper doing a $30,000 remodel would not see it get back $60,000 more in sale price .
Costs are something a well informed buyer would be aware of, but their actions are not always in line with the cost regardless. Some buyers simply will not buy a house needing work, no matter if minor. Others expect a steep discount. Others might want a seller concession equal to the cost. And so on. In today's very tight inventory market, I see houses needing repair or remodel getting high prices that even 6 months ago they never would get - it sells for the same price a good condition house sold for 6 months ago. So in this market, most buyers would not expect, or get, any discount on a repair.
Reconciling on lower end of value ( or in this market, perhaps no adjustment ) is more reliable, or the better word is credible, because it reflects most probable reaction from typically motivated buyers as seen in the market on many sales/feedback from agents etc. Whereas making a precise $ amount adjustment based on the cost is saying you can predict all the buyers on all the comps would have paid exactly that $ amount less.
Many clients on front end are not sophisticated enough to know the difference and might let a cost to cure as the adjustment through,- an appraiser gets no pushback , they think it is ok. Well, we have the different views and reasons for them here.