Buried in that report is the line "because the MoD is no longer expecting to sell some of its Typhoons to Oman in a £600m deal".
In other words, "Instead of Tornado GR.4 carrying on until F-35C starts to arrive, more Tornado squadrons will re-equip with Typhoon than previously planned, with some of those operating the 'obsolete by 2015' tranche 1 aircraft to transition to F-35C".
Reads a little differently that way, doesn't it?