“Beginning with calendar year 2016 returns to be filed in 2017, the automatically extended due date for the calendar-year return could be as late as November 15, 2017…. The automatic extensions that are linked to a sponsor’s income tax filing deadline should likewise be subject to the extended limitation, and the filing deadline applicable to [a ‘direct filing entity,’ such as a master trust, pooled separate account, or certain other commingled vehicles,] should be extended by a month…. Until the effective time, however – including the next filing season, i.e., returns for plan years beginning in 2015, that will be filed for the most part during 2016 – the maximum extension available will remain at two and one-half months.” (Ford & Harrison LLP)