I teach this very thing just about every day. The promulgated upper limit is available for use. It contains all buffers for the activity, be it aviation or non-aviation. In this example, you are able to transit above the area at the upper limit of 2500ft. Although MATS is the defining document for ATCs, the quoted AIP reference also indicates the same answer. This reference is AIP ENR 1.4-10 Para 5.4.2.
Cheers,
NFR.