I very much doubt he's blowing you off. I'm betting that he either doesn't have a clue about the TSB, or for some reason the TSB doesn't apply to your X3.
One TSB refers to "F25 with the N55 engine from 7/2010 (SOP) to 12/2011". The other refers to "F07, F10 and F25 with either the N52T or N55 engines and 8HP45 transmission up to 1/16/2012". It appears that the build date of your X3 may determine whether or not the TSB applies.