Surface winds are picked up about 10 meters above runway...this wind is essential,not winds at 500 ft.
You enter the flare around 30 or 500ft?
Do you look at the FMC at 30'feet?
The tower reported winds would be used in a court of law id think.
If you land with only a few knots to spare,id suggest to reconsider.
Since when winds at heights above your flare height have anything to do with your landing distance?
If atc is untrustworthy,PM at flare initition (50'feet for general landing calculations)may call out TW component.