You are likely sending the Appraiser a letter outlining your request. Make sure that your letter either:
(a) tells them they have a choice and specifically labels Rockport VAL as a valid choice.
(b) if you want to guarantee your data stays your data, label Rockport VAL as the preferred or required option!
For example:
If the valuation of the property includes the Income Capitalization Approach (both direct cap and discounted cash flow analyses), you are [required/requested/encouraged] to utilize Rockport VAL. The VAL model and reports shall be provided using the Rockport VAL platform ‘Share’ feature.
Silence leads to misunderstanding.