To help you prepare to ask your lawyer for advice (or to ask the plan’s administrator to instruct you), you might read:
ERISA Advisory Opinion 2013-03A (July 3, 2013) (Principal Life Insurance Company).
https://www.dol.gov/sites/dolgov/files/EBSA/about-ebsa/our-activities/resource-center/advisory-opinions/2013-03a.pdf
That interpretation includes EBSA’s view that, even if an arrangement involves no set-aside, a contract right to have some amount “applied to plan expenses” could be the plan’s asset.
A plan’s administrator should not rely on the investment or service provider’s description that an arrangement is not plan assets. (1) It can’t be prudent to rely on legal advice from a person that denies that it provides legal advice. (2) It is imprudent for a retirement plan’s fiduciary to rely, without further steps, on advice from a person that has an interest (other than the plan’s interest) about the subject for the advice.
Further, if something is plan assets, the plan’s administrator might want its lawyer’s advice about how to allocate the plan trust’s assets. This might involve careful readings of the plan, its trust, and the plan-expenses arrangement.
Not every plan-expenses arrangement has the same terms, and (even within IRS-preapproved documents) governing documents can state different provisions about how to account for and use an arrangement.