Ann: Further Significant Megabit Success, page-857

Later in the original announcement they address retention further:-

At this time the upper limit of endurance is unknown because the Company has a finite capacity due to equipment
and manpower to test the upper limit in this analysis period. Additional analysis will be done over time.

Retention persistence is clearly evident but remains an addressable priority that will be driven by industry and
potential strategic partners as to what level of retention might best define their strategic and commercial plans. As
such, robust retention testing was not prioritized in this test cycle.

It seems to me they have measured some retention but they're not quantifying retention yet because it hasn't been a focus, due to the above limitations of testing, and they simply do not know.

If it becomes a focus they will work on it depending on needs.

The two recent announcements regarding megabit metrics have a ton of info in them.

More than we've ever got before, and none of it is bad.