Thank you for the reply! 

For the 66 °C data, you have only listed a value of true stress of 1e-6 for a plastic strain of 0. Does this mean that ANSYS will continue to use a true stress value of 1e-6 for larger plastic strain values at 66 °C?

Could you explain how this corresponds to resetting both stress and plastic strain?

How does this ensure a plastic strain of 0? It seems like the plastic strain could still be a larger number at 66 °C, and doing what you suggested will just ensure that the stress remains low at 1e-6.