the axis you need. If your rotation axis is Y, these are for Y. This was just an example on how to make rotation. make sure the key frame passes "+/-180" explicitly, otherwise, rotation will look crazy on approaching and after passing this angle value.
have you checked changes in ZModeler by re-importing an animation file? it should show "target duration" changes respectively.
Alternatively, drag&drop all tracks into editing area, select full range of keys with right mouse button and use tracks scaling tool to rescale selection. I might be needed to combine these changes with update of "target duration" value too.