I'm with you. Double the workouts could mean double the gains when you're on a cycle. The S.A.I.D principal - specific adaptations to imposed demands. Unfortunately it could be double the potential for joint injury. So, training smart is key.
The reason we can't workout as often when we're not on something is because of delayed recovery, cortisol, fatigue and whatever else.
These are not of as much worry when you're on a cycle. I say train as often as you feel you can.
Many people don't realize how many times a week they're indirectly training muscles like bis and tris each week anyway when they're not on a cycle.