tax depreciation schedule

hello has anyone done a depreciation schedule done befoure the house was built and had it done of the plans ?

I have had a quote from BMT and they can do it $100 cheeper then going on there and site doing it , my question does this sound like a educated move or would they miss out of certain things?

my other delimea is if I wait to the build is finished there might not be enough time befoure tax time as there has been some hold ups now its back under way so will be close

daniel