Two Cable Sensors Question

We have been recently using a lot of sensors on our robot, including iterations of 5 encoders or 2 encoders and 3 ultrasounds, and one of the sensors never works. If we have all 5 encoders plugged in, the one in ports 3&4 does not work or even show up in the debugger for RobotC. With the ultrasounds, again the one in 3&4 never works. We switched to a potentiometer on the arm and moved one of the ultrasounds to the ports the arm encoder was in, and that fixed the problem, but is there a limit on how many sensors there can be with two cables coming out of them and where they can be placed?

The 276-2194 digital ports 4 and 10 map to the same interrupt of the User Processor. This causes a limit to the number of two cable sensors.