I interpret that statement as meaning that there is no additional activity involved and one does not have to allocate an "action" (of which one can have only three per round, one each of snap, normal, and deliberate) to the SCSM in addition to the spell-casting action. There's nothing there about it not requiring an additional roll for getting over the normal spell-casting hurdles.
Okay, I'll stop being lazy and check the book: here's the text from page 105 of RMSR: "If this maneuver is successful, the spell may be cast with the same normal failure chances outlined above." The SCSM does not bypass the normal spell-casting rolls, it is in addition to them.