Not always. Somebody always has the 1) largest house, 2) smallest house, 3) largest/best lot, 4) largest/most outbuildings, 5) the strangest design (dome home, log cabin, earth sheltered house, mobile home attached to a stick built home), etc.. I've appraised enough of those types of SFR to know that bracketing is not always possible.
As an excellent reviewer once told me "If you don't have good comps, tell me a good story". Explain thoroughly why you did what you did. Might take some extensive narrative but if adequately explained, there shouldn't be an issue.