Ohh I see it now, yeah thats weird, but I think it is because they didn't make a whole new model for the A321, only added two extra body section, as I figured from the textures. All have A320_Main1.bmp and has a A321_Various2.bmp containing the extra section textures. And yeah..On the panel the litllte table or whatever says: OO-TCK; MSN 343, which actually is a Thomas Cook A320-212 http://goo.gl/n9zm6
So this could be answer for that. I never realized it :D