Look at it like this. SIA would need around 15-18 months (mostly 18) to complete the MPL license program. So if the program starts December, we're looking at August 2016 for completion. Now out of 18 months, 7 months is spent in ground school which is totally independent of whether one is doing CPL or MPL. So if SIA desperately forecasts a need for pilots they might start recruitment by around October 2015 for new batches starting Jan 2016 so that ground school can be completed by August. If not then we have to wait patiently till April 2016 for batches starting after August 2016. I would think it would be the latter but you never know.
It all depends on their demand and so far it doesn't look like they'll be needing more pilots and initially they will just replace old planes with the new ones coming in and not increase their fleet size. I hope I am wrong though.