You had the information you needed (that two properties are involved) when the LE was issued, so I don't see any argument for a changed circumstance here. It's an error, plain and simple, and, unless the borrower fails to provide intent to proceed until after the expiration date and time of the LE (ten business days unless you gave a later date on the LE), you're stuck with a 10% tolerance limit.
I think you have grounds for trying to have the title company share some of this burden.
John S. Burnett
Fighting for Compliance since 1976
Bankers' Threads User #8