NB: 1 leaf = 2 pages.
From a Mashcat 2012 session: see the write-up for more details. There is now a version to handle lots of calculations at once, e.g. from a spreadsheet file, here. Referred to in an RDA JSC Discussion Paper on Machine-Actionable Data Elements for Measurements, Extent of the Carrier, Pagination and Foliation, Dimensions, Extent of the Content, and Duration (2015), page 4.
Thomas Meehan (Orangeaurochs)