Technically speaking, when you are in bankruptcy, your trustee should have power in the decision making and not you.
From your perspective, I would think that the higher the amount, the better it is for your loan restructure. Don't you think so?
As to you have a question, or you would like to have the value changed, I would suggest you to communicate with the Trustee to get his/her permission. Just submit your questions (or challenges) to the two appraisers you already have. They can fit the factors to their formula and model and recalculate the values easily. I am not sure anyone on line can do the calculation. Also, the authority for this new amount in court or in your proceeding is not established. The appraiser I believe has to have some type of credential in your state. And usually, they are retained by the attorneys in this type of case.
p.s. Just between you and I, consider the value between the two alternatives and lean towards the one that is beneficial to you and your plan.
Fiona Chen, MPA, Ph.D., CPA, ABV, CFF, CITP