ITAT President was a successful lawyer before joining the Tribunal!
How does it matter? We also wonder. But the website of the ITAT says that President Vimal Gandhi's Earning as an Advocate was more than the salary offered to Member, ITAT in 1985 when jointed As Judicial Member.
We really don't know what they are trying to convey. Does it mean that other lawyers who join the Bench were not earning as much as the salary offered to judges. Most often, any lawyer who joins the Bench of a High Court or Tribunal would be earning far more than the salary offered.
See http://itat.nic.in/ITATCMember.htm