I am in the process of getting a single wide manufactured home refinanced w a portfolio loan from a local bank. My appraisal has just come back lower than expected and the comps used I feel are not appropriate, however, I am unsure. Looking for some insight.

My home is on a permanent foundation and purged to 3 acres. The appraisal is making its conclusion mostly based on 3 comps. 2 of the 3 comps used are also manufactured homes but not purged and not on foundations. They have each been adjusted $6000 for this fact. I feel that these are not fair comps because the lack of foundation prevents the home from being classified as real estate (right?). More importantly it prevents the home from being financed by mostly all lenders and therefor greatly restricts pool of potential buyers and therefor the resale value. Is there any appraisers out there that know what the guidelines are around this? Are these fair comps? Thanks!