I'm working on a 500 V- 90 V adjustable power supply based around the LT8312, so on my way to designing my own version, I made the typical application circuit given on the first page of the data sheet in LT Spice. I'm in a pickle in that it puts out in simulation only about half of the voltage indicated. This also looks like the example LT Spice file given on the website when you take off the circuit elements said to speed up simulation time.
What gives? I've attached my LT Spice file to this ask. Can anybody find a glaring error and if not then in which way am I operating outside of the LT8312's envelope?