Using the 180s for Manchester Airport to Scotland would seem to make sense. However this would presumably lead to the peak trains from Manchester that are currently formed as 2 x 185 seeing reduced capacity and as these are very busy to Bolton (usually possible to find somewhere to stand) that could be a problem.
There does seem to be no real reason not to add the Barrow or Windermere 185 to the Blackpool service that runs half an hour earlier and then in the worst case scenario make it wait at Preston to run in its normal path (thorough passengers could still get the xx15 from Piccadilly and change at Preston). This would then add useful capacity to the Manchester to Bolton/Chorley/Preston commuter flow and maybe that is what they are thinking of. (An added bonus would be that the xx45 from Piccadilly calls at Horwich Parkway improving conditions for anyone wanting to park and ride from there)
Scotland-Manchester trains become a new franchise in 2012, with electrified stock as soon as the manchester-Liverpool bit is electrified.