Portal 63 Reward?

[GoDFaDDa]

We have found this reward to be very confusing. How long can the player who completes the mission buy maneuvers at 4 less cost? Is this good for just one maneuver, or is it good for all of the maneuvers they buy on this turn? Or, because the mission card goes to their point area (and not discarded), is it good forever?

We were assuming that it was good for one purchase, because it seemed very overpowered for what it was.

[Mr. Domino]

All mission rewards last until the end of the turn on which they are earned.

[Jan Horinek]

Rules, page 15, paragraph Mission, the last sentence.