English to Spanish Medical Medical: Health Care Healthcare insurance

Hola a todos:
Estoy traduciendo un seguro médico para una empresa y dice lo siguiente:

■ When Covered Health Services are received from a non-Network provider, Eligible Expenses are determined, based on:
- Negotiated rates agreed to by the non-Network provider and either the Plan Administrator or one of the Plan Administrator's vendors, affiliates or subcontractors, at the Plan Administrator's discretion.
- If rates have not been negotiated, then one of the following amounts:
♦ For Covered Health Services other than Pharmaceutical Products, Eligible Expenses are determined based on available data resources of competitive fees in that geographic area.

♦ When Covered Health Services are Pharmaceutical Products, Eligible Expenses are determined based on 110% of the published rates allowed by the Centers for Medicare and Medicaid Services (CMS) for Medicare for the same or similar service within the geographic market.

♦ When a rate is not published by CMS for the service, UnitedHealthcare uses a gap methodology established by OptumInsight and/or a third party vendor that uses a relative value scale. The relative value scale is usually based on the difficulty, time, work, risk and resources of the service. If the relative value scale currently in use becomes no longer available, UnitedHealthcare will use a comparable scale(s). UnitedHealthcare and OptumInsight are related companies through common ownership by UnitedHealth Group. Refer to UnitedHealthcare's website at www.myuhc.com for information regarding the vendor that provides the applicable gap fill relative value scale information.
Alguna sugerencia para el término gap/gap fill? Se refiere a una metodología de diferencia?

Muchas gracias!
Belén