NCM 7.1.1 and before require a Windows Administrator account in order to call the NCM jobs to run. These don't have to be AD accounts, but these accounts must have Windows Administrator rights on the NCM server in order to run the job at the scheduled time.
NCM 7.2 and above removed this requirement, as such NCM jobs in 7.2 and above do not use any Windows credentials in order to run at their scheduled times.