The sold price is contract price. That is what you enter on the MLS. You use other fields to identify concessions.

Please don’t cry me a river about affecting comps. I made many a posting way back when I complained that comps are horrible using the MLS. Not because of 10 or 20k missed due to additional cash needed to close but because of loan mods of large sums of money that are not recorded, and not identified in any manner. So you can be buying in a neighborhood where MLS comps say one thing, but 7 homes in near proximity have loan mods done that are not recorded or identified in any manner.