Thabnks for the plug, Jeff.
Me, I never understood the Ascension class - why make a DN with a secondary hull that's SMALLER than a Conny's? Don't make no sense.
Well, I always took it that the Ascension secondary hull was nothing but engine space and a hangar with a pair of shuttles... no cargo, no living space, no botanical stuff, none of that stuff. Just a pair of engine cores, cooling hardware, controllers, etc... but nothing else.
Basically, the Ascension would be the "stay close to base" version of the Command ship and the Federation(r) would be the "distant deployment" version.
Both are equivalent in combat and C&C capability, but one has longer range and can serve in a few "multi-purpose" roles (due to the cargo space) and one is a bit faster (due to reduced mass).
That's the way I've always seen it at least.