Where a Reviewable Services regime is contemplated (see section 2.36), the operating fee may be split into reviewable and non-reviewable components. The Reviewable Services regime, as set out in the SIPD, provides for periodic review (at intervals of between 5-10 years depending on the nature of the Reviewable Services) of the pricing for each Reviewable Service, to ensure alignment of each Reviewable Services component with prevailing market rates.