Hi Frank ! Sorry I've been slow to respond but I've
been on the road and I wanted to explain this clearly.
Sit down and fasten your seat belt...

The ILEC SN10 calculates final glides for arrival
at the MC cruise speed. Simple glide page,
alternates, as well as normal task. That's not
always what everyone expects but does help
avoid subterranean arrivals.

Change MC and the deficit changes...

Hope that's clear !
Best Regards, Dave "YO"

PS: Thanks to gil who guessed correctly !