...but gets the day over faster, and if you're close to FDP limits (ie ops normal), you at least don't have to extend/call out the suckers.
Econ Mach and 300KIAS myself
As for CI, 15-28, precalculated by our flight planning software. The higher value is usually for the shorter legs (1hr) vs the lower value for the longer legs (2hrs). I don't query the computer. I just punch in the numbers.