hello
I have encountered difficulties in calculating the loss of dual pulse test with PSpice. I need your help for two problems.
This is my circuit diagram, attachment 1 is my simulation file.

I calculated the loss according to the conditions on the datasheet (as shown in the figure 1 below). The voltage I measured was 2-pin (MID) and 3-pin (V-), and the current I measured was 3-pin (V-), simulating the situation when the load current I measured was 900A(as shown in the figure 2 below)

Question 1: When I set V1 of V5 to -4V, the simulation results have been stagnant(as shown in the figure below), but when I set it to -3.9999V, it works normally.

Question 2: The turn-off voltage measured by me is 18.665mJ(I calculated according to the calculation requirements on the datasheet and using the S-function), but the turn-off voltage of the Datasheet under the same conditions is obviously greater than 20mJ(as shown in the figure below), and all of my conditions are the same as that of the Datasheet. Why is there such a significant difference? What adjustments do I need to make if I want my simulation results to be the same as on the Datasheet?

I am very confused about these questions, and the answers to these two points are also very important to me. Thank you for reading such a long letter, and I am looking forward to your reply, thank you!