MG2 Temperatures

I recently got Torque pro and OBDlink LX bluetooth adapter. I have been studying several things about my 2012 Prius, but I have noticed that the MG2 temperature really goes up after a long climb (I drive from Phoenix up the hill to Prescott regularly, 6 or 7 miles of continuous 6% grade at an average real speed of 70 mph) I have noticed at the top of the climb the MG2 may be around 230 F. This is with moderate temperatures of around 70 to 80 degrees ambient. I am wondering if some part of the cooling system is not working correctly, or is that amount of temperature creep under a substantial load normal? It does drop maybe 20 degrees back into the low 200s before I get home, once I am out of the sustained climb. The MG1 temperature is a steady 30 degrees cooler, and even at peak-worst case, both inverter temperatures stay below 140. Anyone else have any experience in this matter?