You need to meter your cells. Will tell you if the wall charger is actually charging them fully.
Also using a meter in line will tell you if the cells are able to sustain the draw on them when you run up the motor.

As for why the TP cell is doing better is more then likely in the C rating, it's double the E-flites, so even if it's not being fully charged too it still has twice the capability.

As the motors wear out they tend to draw higher amps. It could be also that the Eflites just don't have the juice anymore to handle the increased draw.