do you mean the free month for the transition we got from being with warner brothers, and then moving over here to sony when the billing changeover came? if so, yes, though it's not "one month of hours of gameplay", but "the right to log in for a 30 day period"... i.e. you have unlimited time to be jacked in for the month you have paid, and it counts it whether you are are jacked in or not.
so for example, when the billing change came, i took a couple of weeks off to do all the stuff i hadn't been doing since i was jacked in all the time, instead. the billing changeover came on august 15th (i think that was the date), and i came back on september 2nd. when i signed up, i did as you did, got the one month deal again, and my "next billing date" or whatever was november 2nd, so my free month was clearly included.
this depends when you came back, however, come to think of it. i think the changeover rules said something about having to activate your account by september 30th to be receive the bonus month.
lastly, if you mean the time you had with warner brothers, that's a good question. i recall being lead to believe that our time that was already paid for with warner brothers would be transferred over and added to our sony accounts, and if we hadn't transferred over warner brothers would send a check for the remaining time. don't know about the check, since as i indicated i moved over to sony after a couple of weeks, but my account definitely wasn't credited with the time i still had with warner brothers.
so in summation... if you mean the free month from the changeover, yes, you should have gotten it, but only if you transferred your account by september 30th. if you mean the time you still had with warner brothers, i recall hearing we'd be credited for it somehow, but i've yet to see that in any form.
