As a former CPA for many years and now an Enrolled Agent, it's unclear to me what the issue is here.
Unless your client is required to provide some third party Compiled, Reviewed or Audited Financial Statements,
most small business tax returns are not prepared according to GAAP.
In fact, most small business tax returns are prepared using "tax basis" accrual or "tax basis" cash methods of accounting or some hybrid method.
My core practice for the last 27 years is based on providing 'internal use" monthly financial statements which are either accrual or cash "tax basis" statements, not GAAP
The statements that I provide my clients do not have any supplemental notes or disclosures.
My clients have been able to obtain bank loans based on these "internal use" statements.
In fact, in 27 years I have never had a loan officer question or reject the statements that I provide my clients.
As far as I am concerned, until the IRS affirmatively requires the capitalization of operating leases, this is a non issue.