can permitted guest house not on record add value to appraisol?

[Patrick Flynn]

Hi I am trying to get a refi through that got a refer on DU, Borrowers score has gone up to 699 from 679 but his 3 tradelines are with same co, at zero bal he has 1 late on tradeline

he is W2 his ratio is about 46% and DTI 80% +.

But I cant seem to get a true comp that can lower LTV if the guest house is used and the same goes for the income I am using one from Trulia but it does not include GH

the area goes about $500 per sq ft it would increase the value greatly on that alone