Yes you understood correctly. SFI's do not just instruct low time cadets on type courses. They also do recurrent sim training for crew (not OPC/LPC as this requires TRI/E), and OCC courses. As ryanair don't currently recruit direct entry FO's, these OCC courses are for DEC's the vast majority of whom have several thousand more hours on the aircraft than the SFI's. This does not appear to cause problems. As has been said, Ryanair have been using SFI's for a long time now. The company takes a great deal of pride in the standards of its training department, and from what I hear, it is generally held in high regard throughout the industry.