It depends on how much of a backlog that office has. Normally, if they have to request documents they will put the application back in the processing queue. A few Ottawa applicants lately have had document requests, sent the documents that day or the next, and received a decision within a few days, but that's Ottawa. Who knows if they just don't have a backlog anymore or if the CIC is using them as a pilot office to test out some new procedures/policies.
With CPC-M I'm not sure how long it would delay SA. It could be as little as a couple weeks, but it may be longer since CPC-M is so backed up right now.