When a property is added to a scenario a 'Market Value Approximation' is calculated based on for example market rent in the sub market.

You are resonsible for verifying and updating the data used in the calculation. 

 Two important points:

The calculated value is exactly what it is called; an approximation. It should not be compared with an external valuation performed by an appraiser.  

The value approximation should be considered as the starting point. Not the end of your analyse. It is up to you to go through the data and update it to the correct numbers. For example, not use the market rent in the area but the specific rent in the property.