Chris your thread subject is "Escrow example - credit & disability required ?" and I would say you have to include them, but in your posted question you refer to "voluntary" escrows which may give you an out. Review 3500.17 to see if the following gives you the exemption you're looking for.
(o) Discretionary payments. Any borrower's discretionary payment (such as credit life or disability insurance) made as part of a monthly mortgage payment is to be noted on the initial and annual statements. If a discretionary payment is established or terminated during the escrow account computation year, this change should be noted on the next annual statement. A discretionary payment is not part of the escrow account unless the payment is required by the lender, in accordance with the definition of "settlement service" in §3500.2, or the servicer chooses to place the discretionary payment in the escrow account. If a servicer has not established an escrow account for a federally related mortgage loan and only receives payments for discretionary items, this section is not applicable.
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The opinions expressed are mine and they are not to be taken as legal advice.