In order to assess systematics, I implemented the ability to adjust the efficiency by a specified percentage (a relative percentage that is).  The 2 plots below show that the code is working as anticipated:

And I also set up the code so that above a certain pT (currently set to 3 GeV/c), the supplied efficiency is fit with a constant and that constant is used to calculate the efficiency for particles with a pT above that certain pT.  The plot below shows that the code is (probably) working as anticipated.  There are still some wiggles (I was expecting it to be flat above 3 GeV/c).  However, those could be due to the extremely fine binning I used (or maybe finite statistics)...  Either way, it's flat within sufficiency accuracy (see the fits).