I'm afraid you misinterpret the LMG. It's 30 days from purchase of the unit, not 30 days from purchase of a new map.
It's to protect purchasers from buying units that may have sat on retailer's shelves for months ...
I agree you got the short end of the stick because of timing, though ...
I got the short end of the stick also, being not very smart with my TT720.
I thought when I plugged the TT and downloaded the updates it included the latest map. Found out from reading this site that wasn't the case and I was past the 30 day so I couldn't get the update. My TT was on the shelf for a while because I have 705.1 ver. Called TT and got a very big fat "NO new map for you"!