From: Utopia Planitia Fleet Yards
And that makes me think...are they one time use coupons (which is my assumption), or good for multiple uses within the 30 day window?
You can use it once BUT you can buy several products on which the discount will apply. So, in your case, wait for Armored Brigade France release and then buy it with Warplan in the same order. You have one month to use your coupon.
Mine is today or tomorrow, will see
Chancellor Gorkon to Captain James T. Kirk:
You don't trust me, do you? I don't blame you. If there is to be a brave new world, our generation is going to have the hardest time living in it.