Correct.
And that is my point with the flaw in design. Several phones are made the exact way, in fact I've never had this issue with my Touch Diamond, TP2, HD2, Desire HD, etc.
IMO, the Sensation's sudden loss of reception is not normal, despite the antenna's being placed where they are (at least through my past experiences).
I guess we won’t know for sure unless we got a Sensation XE and try to send a text in landscape mode, lol...