If a concession is around 2% of sale price or under, it is very difficult to tease out if it was an influence on sales price unless the property and the comps have a high degree of conformity. In my area, realtors and loan agents typically manipulate a sales price percent or so in order to accomodate a seller concesion. They usually withold contract addendums re concessions until after the appraiser has submitted the report. It is kind of hard for an appraiser to retrospectively say a 1% concession had an affect on sales price! As long as it is up to us to determine if a concession has influenced a sales price, realtors will continue to play their tricks. Ultimately, the FNMA should step in and mandate that concessions over say a 3-4% benchmark are inducements and not allowed. That would help curb the abuse.