So, I just picked up a FS700 and wanted to take advantage of the super slo-mo, the question I have is I have seen quite a few videos where the action is normal speed and then seamlessly goes to super slo-mo, can that be done in-camera or is it done in post?
You would use a program like After Effects which has Time Remapping (does exactly what the name describes) or a plug in called Twixtor for After Effects which does it even better (but you have to pay extra for that).
Premiere Pro has an envelope you can select over the clip called Time Remapping > Speed. You would set that to 1000% for real time, then create a keyframe (CMD/CTRL click on envelope line) and then bring it down to 100% for slow-mo playback.