I must compute penalty for not paying estimated tax in 2016 for a trust. Form 2210 says a trust must use 11/30/16 as the end date of the year. (see details).

To compute the penalty, Form 2210 uses 11/30/16 as end date for the year for trusts, although for individuals it is 12/31/16. My question is, how do I handle trust income received in December 2016? Its very confusing - is the trust not responsible for a penalty on December's income?  Is December's amount supposed to be computed the following year?   Thanks for any light to be shed on this.