On Thursday, November 15, 2018 at 5:19:16 AM UTC-8, wrote:
In my experience with the USAFA glider program, both as a cadet instructor and later as the officer-in-charge of the advanced soaring program, the vast majority of students achieved the end goal of the Airmanship 451 program, which was to solo. That act completed the course.

Has the AM 451 curriculum changed whereby most students now do *not* solo (which would have to be the case to "more than double the solo rate")?

The sims were used in the AM 251 course, the "Into to Soaring" course given during the summer for 340 students, not the AM 451 which is used to train the instructors. The AM 451 course only has about 60 students, and yes, most of those have already soloed, or come close, in AM 251.