It requires approval if it is on a regular workday (shift)  

If the pilot self-schedules himself at a time he is normally off, no approval is needed.   If he self-schedules himself on at a time he is normally working, he needs approval.   Call it approval, pre-approval, whatever, but it isn't approved until it's approved.   Simple!

Union letter was not clear, and full of nonsense!   Steps 1, 2, 3??   Nonsense!   Isn't in the CBA that way, you're making stuff up there.

15.1 C says the RAD "Training scheduled during periods when a pilot is normally scheduled to work at a base require approval by the Regional Aviation Director."  RAD doesn't have to approve training scheduled where you've scheduled on your off week.   Only for your on week.

If you are outside the 60 day period, you are free to pick dates whenever you wish, and seek RAD's approval for times you've picked that conflict with your shift days.   CBA doesn't mandate him approving those dates, it gives RAD total discretion.   If you don't pick dates outside the 60 days, they will pick them for you!  It becomes mandatory at that point.

If your currency lapses because you don't go training before it lapses, it's on you per 15.1 B   You'll be on unpaid leave until you get current.