Mobile Home Park Appraisal vs Industry Formula

[Andriy Boychuk]

The industry standard formula to evaluate a park is

# of lots x caps x 12 months x expense factor x lot rent ($)

I understand it is basic and we should consider the market and etc. 

I do my offers based on the formula. However, many park owners come back to me with unrealistic (2 times or 3 times) asking price. They based their asking price on appraisal they did with real estate appraisal. How is accurate part appraisal? Is it is not very accurate, how can you explain it to a park owner?