Among other things, the increased demand for skilled supervisors needs to be matched at the SSM area, and there are a number of practical issues related to day-to-day supervisory work, including language issues, yet to be fully ironed out.
Nevertheless, even a one-time price change affects inflation for a year, simply because we gauge inflation on a year-over-year basis. Some temporary factors are themselves gradual rather than one-off, such as increased competition in retail food stores. This all serves to underscore the data-dependent nature of monetary policy.