The stated string gauges in the stated tuning would in fact be very slack. Back in the day we all played 13-56s in standard tuning, and for a while in the 80s I played 13-58s in standard tuning.

http://www.daddario.com/DAstringtensionguide.Page?sid=66a480c0-de5c-4667-97b6-35819ce6a1ce

And IIRC the Martin lifetime warranty is only in favour of US purchasers.