On sx160, I noticed wheel_left() and wheel_right() didn't work from chdkptp.
The wheel buttons in the chdkptp GUI did work.
For reasons I don't remember, the chdkptp GUI buttons use PostLogicalEventToUI directly instead of the wheel functions. The wheel functions on this camera and many others use PostLogicalEventForNotPowerType rather than *ToUI.
Switching to ToUI fixed the wheel functions. It seems likely that other cameras suffer from the same problem.
The difference between these functions has never been clear to me, but we've seen cases before where some events only work with one or the other.
waterwingz found that the wheel_* functions on G10 also did not work, but in that case it turned out the levent IDs were wrong. With the correct IDs, both *ToUI and *ForNotPowerType appear to work.