In the McCoy v. Oakins decision, the court determined that the payor was not intentionally underemployed. Some of the factors that were before the court were:
1) insensitive message sent by payor to payee that he will be out of work when the matter would return to court;
2) payor refused to pay for child care as per the agreement between the parties, even though the payor paid for those expenses prior to separation;
3) payor was on the longest lay-off that he has ever had;
4) previous employment seeking behaviour of the payor;
5) payor’s credible evidence; and
6) reasonable behaviour of the payor in securing employment.
http://www.canlii.org/en/on/oncj/doc/2015/2015oncj677/2015oncj677.html