In the 3rd level ability under the 'Projected' Alternate Class Feature (GM p. 38), it says you can use a move action to give yourself concealment for up to a number of rounds equal to your Witchwarper level, though they need not be consecutive, but it doesn't appear to say anywhere when you regain all of those rounds.
Is it with a 10-minute rest, like the 6th level ability, or does it require an 8-hour rest?
I would lean towards per day. Usually when I see the 'rounds/minutes per level, though not consecutive style' of writing, they tend to be a per day abilities.