It's the same timing, it's just a matter of preference for how you start. The gentleman can start the box with a forward step on the slow, or start with a side together (Q-Q).
I find in American rumba it's easier to start with the QQ rather than step towards the lady for the very beginning of the dance. Once you start, there's no difference between QQS and SQQ (it's still two quicks and one slow)
hope this helps