How fast can the power supply update? I am not familiar with that equipment, but 130 ms does not seem out of line. Many GPIB instruments take that long or longer to update. If the instrument ever needs to change rnages between successive values, the delay might be longer. I am using a Keithley electrometer which updates in 360 or 720 ms, depending on range.
I don't use the DAQ Assistant so I am not sure how it behaves. Parallel loops need to have a wait function in each loop to allow LV's internal scheduler to share CPU resources between the loops. Try adding a Wait(ms) function in the DAQ loop with the wait value = 0.
Lynn