Ok, but 2 static PDCH is not enough to handle all the traffic. What matters most is the dynamic PDCH’s.
What are your parameters to control those dyn PDCH ? And what are their values ?
also, ensure that you can put at least 4 TBF per PDCH, in both directions. This is a way to multiplex several users on the same PDCH.
also, you can try decreasing the number of PDCH per TBF. Instead of 4, you put 3. (not less…)