Yeah, this is a weird one. In S&F with WAV, your frame rate caps at 60 -- you can get 120 in plain S&F, but not S&F with WAV. Weird. Thanks for pointing this out, I'd missed that. It is actually mentioned in the manual -- page 115, "Notes" -- but it would be easy to miss.
I would hope that they could improve this; yes, the camera is handling more video data than the C70, but then it should have a more powerful processor. So this is an odd regression. Fingers crossed for a fix.
