Answer: The "shtibel" system makes sense for people whose daily schedules differ. But it is not right to alternate where you pray daily according to how late you sleep on any particular morning.
First of all, our Talmudic Sages have pointed out the importance of having a fixed place for your prayers, a concept that seems to include the need for a fixed time and fixed minyan.
In addition to the quality of prayer in a fixed frame of time and place, there is the social aspect. Praying together creates a valuable bond of friendship and missing out on your regular company may even raise suspicion regarding your seriousness towards prayer.
In conclusion, make it a habit to pray together and stay together with your fellow worshippers.