Panzer Tactician costs 30 munis. Concealing Smoke on flak track is actually free. The M20 and AEC also get smoke AND are non-doctrinal. Note that Panzer Tactician takes up one of there doctrinal abilities slots.
You're right, in addition to a cost increase, all of those such abilities should have double the cooldown.
They really all could use a simple cost increase to hurt a player making regular use of them. 30 muni to save a tank is like giving someone a wire in return for a new laptop, and keeping a rushed M20 about longer is still very powerful.
Except for the Flak's, I believe it being free is entirely acceptable considering it is a defensive unit that requires being entirely still to shoot making it easy prey for just about AT with a bit of range.