veteran corporate director and business adviser with a law degree from Osgoode Hall Law School in Toronto. (Linkedin/CBC)

Castelli's appointment was renewed by the Harper government, along with several other government appointments, in June 2015, just weeks before the federal election campaign began.

When the Liberals came into power, Castelli offered to step down, though he told CBC News he was "willing to stay on." Last month, however, he resigned permanently.

CBC News reviewed Castelli's per diem claims over a 16-month period. He charged for a total of 73 days, or just over $27,000 in per diems during that period. Just over half of his per diems appear unrelated to attending board meetings.

However, the CCC insists all of the per diems charged by Castelli are allowed under its rules, which haveKay, who was also appointed to the CCC by the Harper government, currently serves on the boards of two private companies and is a deputy judge with the Superior Court of Ontario Toronto Small Claims Court Branch.

CBC News reviewed Kay's per diem claims over a 36-month period. He charged for a total of 424 days earning $159,000 on top of his annual stipend. His average annual compensation at nearly $62,000 was more than double Castelli's.

CBC News took a closer look at more than half of the perdiems claimed by Kay, and the vast majority of them appear unrelated to attending board meetings or were paid without a clear explanation.

In one example, it appears he claimed a per diem for attending an air show in Paris.

"It's ludicrous," says Ken