OC solo and CCR solo are completely different animals. Current gen CCRs by nature have failure modes that are much harder if not potentially impossible to recover solo.
I love solo diving on singles or doubles, it is my happy place, but I do not dive my CCR solo and refuse to do so until the sensing technology gets better - regardless of my level of hours or certs on the loop. That is my personal line in the sand, others here disagree and choose otherwise. My point is, think long and hard about the realities of surviving a catastrophic CCR incident alone. Do you feel you could recover solo from a bad CO2 hit or late-caught hypoxia incident?