Perhaps they have done an analysis of the type and number of callouts Sumburgh get and identified that they are mostly long-range or medevac style ops rather than the short range quick jobs you get at flights in busy tourist areas.
That is what the MCA's online modelling software provided during the bid process.
Then they awarded a contract based on all of that, getting it for a price that is an estimated (JF) 1.3%pa below inflation compared the last one, and then ... ... something else ... what?
