Montgomery County’s inspector general issued a report on Friday urging the county to be more diligent in challenging commercial property assessments conducted by the state, some of which appear to be unusually low, The Washington Post reported.

Inspector General Edward Blansitt said that a study of 20 commercial properties found that those that sold recently for more than $10 million were assessed at an average of 68 percent of sales price.

Buildings that sold for less than $700,000 were assessed at 90 percent of sales price.