I agree, they all do required at least two years of tax returns showing self employment, but the 'comfort letter' is just a waste of time.
Even when a tax professional does write a 'comfort letter' for a small business (that they don't do the accounting for), the letter really doesn't say anything useful anyways. It usually says something like "according to what the taxpayer told me ... " and indicates the tax professional does not have any information beyond what the taxpayer said.
