I'm not sure how the institution of Control Commissions even came about. My recollection is that in the underground period of the early 1920s hearings on violations of fundamental party rules were dealt with by ad hoc committees of the Central Executive Committee, generally of 3. These were appointed on an case-by-case basis by decision of the CEC itself at its regular meetings.
By the late 1920s, a regular Central Control Commission had emerged.
How and when this change took place — of this I'm not sure.