As I remember, the "Shaw-Fujikawa Translight Engine" (along with its Covenant and Forerunner equivilants) send and only send you in and out of Slipstream space, where you use your own momentum to travel.
This means that the many pages with "2.1ly/day" on are incorrect, of which nearly all human ships have it on their pages.
As a Cruiser is faster than a Corvette in normal space, it too is faster in slipsteam space, thus will arrive at a targetted location faster.