I've done plenty of SBA appraisals, including on owner occupied properties, but the majority include the income approach. Could it be that the engagement letter requests that you do the sales comparison and cost approaches, but that they aren't necessarily requesting the income approach? If so, that doesn't mean that you are not to do the income approach-that is your decision to make on whether it is applicable. I am always wary of when clients request that I do not do an approach-it is hard enough to come out to the right value in many cases and if you omit an approach that is applicable in your eyes, your results may be that much less credible.