An admin shuffle is what I read it as as well. Duties of some units being covered by others during certain times.
Probably should have been on of the QSXXX codes
SERVICES
SA ATIS
SB ATS - REPORTING OFFICE
SC ACC
SE FLIGHT INFO SERVICE
SF AFIS
SL FLOW CONTROL CENTRE
SO OCEANIC AREA CONTROL
SP APCH CONTROL SERVICE
SS FSS
ST TWR
SU UAC
SV VOLMET
SY UPPER ADVISORY SERVICE