It is to assess the effect upon on-time-performance, the measure which is so important to airlines these days. Recent traffic growth at MAN has put pressure on 'Slot 2' which occurs in the early afternoon when the airport has been running on a single runway.
Wasn't the entire premise of the multi-million investment, the lengthy planning permissions process etc etc to allow MAN to cope with "traffic growth". It seems ironic that 10 years after opening, a trial is needed to see whether it has any impact upon on-time performance