but, the basic principle is:
Models hired from outside the player's chosen faction (Master's faction i think) cost +1 ss...
..., models with the mercenary characteristic, and models permitted to join the crew through any other special hiring rules. Models hired by a crew must meet all special hiring rule restrictions or they can not be hired.
page 71 (RM)
i think m&su is not a special hiring rule.
so, must pay +1 ss.