compadre (student, also) to YB and Guru Dev...Could be specific to Kundalini in form. This is YB's (Yogi Bhajan's) practice...
As to your wider interpatation- here's what this is specifically about- In Sanskrit there are the Amrit Vela hours- those hours of sweet ambrosia during which the windows of the worlds are open- So the time is specific- The worship is done at this time with purpose.
Then to the form- always for me it has been sanskrit prayer, yoga, rest, & mantra-always at this early morning time. Time is inflexible in KY- or should I say it is always between 3-6 am