if the pd channels are on different carriers its of no use as the user will get only one frequency at one time. Take one site only, balance the dsp overload if any, shift all the sd channels on non bcch, leave the default channels like fach on bcch and then test the throughput i am sure you will get results. We were earlier getting only 13kB At max but now have gone to 30kB with 2 static and 2 dynamic config.