Hence the explaination which explains why he just received his Dec issue, and his Feb is still floating around in the Pacific somewhere
I think a lot of having the issue come out before the actual month probably has a lot to do with a "perceived benefit" to having a subscription, you get it before it appears on store shelves. Also once it hits the shelves, it can be out there circulation for a month or two and still be a "current" issue which stimulates sales as well. Otherwise the issue is "old" after having been on the shelf for a few weeks and is less likely to be sold.
It's all about marketing my friends. All magazines do that.