Well that's a philosophical kind of question you ask ... titled 'race to idle'.
The idea is correct, best should be to do stuff as fast as possible (high freqs.) and get to sleep asap, to save juice.
Though that seems to prove right while screen is on and CPUs are (one at least) awake, that looks not so while screen is off...
I suppose that could come from typical screen off processes needing way less computing power but the governor spinning up the freq. too high unecessarily, hence wasting juice, lag not being an issue in such a case as for syncing for example it doesn't matter it it takes 1 or 2 seconds.
See if for sending a sync request for say your contacts CPU freq. revs up to 2GHz, then waiting for the reply for half a second or so freq. doesn't rev down fast enough, the same process could have worked at much lower freq. which over that timespan would have saved juice, especially on such hungry CPU as our powerful Cortex A15.
But this are just suppositions...
I just tested it to see which theory would prove right, looks like it was worth going there
JP.
Send from my 'proudly eFused' Note 3 (n9005) running Yank555.lu v0.7 kernel.