Does your powerbook rock?

This may well sound like a crazy thing to be asking but i wonder if there is a problem with powerbooks not resting firmly on the four corners but instead rocking like those rather annoying tables in restaurants, bars cafes etc etc. My laptop does not appear to be level and the lower right corner is not at the same level as the top left.

The problem might at first sight appear to be cosmetic, but I wonder if the heat generated near the power inlet (top left) when connected to the mains might have caused the metal to have warped and therefore resulting in this rocking.

I am absolutely certain this was not an issue when i bought the laptop about 6 weeks back. Also this is not the problem with the table as i have tried it on a number of different ones and also positioned the PB at various places and angles. The rubber inserts at the corners also appear to be fairly evenly set.