Fifty days gives you a reason to ask questions, not an automatic discount. I’d compare the listing date with any price-cut timing and check whether similar stock was withdrawn rather than sold. A seller who has already reduced once may react differently from one testing the original price. Also...
I’m not convinced a larger percentage alone solves this. The key missing fact is whether the studio remains occupied or operational during the works, because phased access can create more sequencing risk than the finishes themselves. Before fixing the contingency, request a room-by-room...