Given the history of the Poser Developers I wouldn't trust them to put any animation functions in to Poser itself. Maybe if they made all the Animation features available via Python that would be as far as I trust them. AS an example for Poser 10/2014 they added the collapse feature that was suppose to combine the movements of several layers into the base layer. For all of Poser 10 and through SR4 IIRC of 11 it was broken. That is the program took a frame added all the layers together and then was suppose to place that value onto the base layer. It added all the values together and also added in the value from the prior frame. So what you got was a value that could quickly skyrocket to extreme values. A Sine wave that should have gone up and down around the Zero axis became a stair case heading for the sky (or basement if starting in the negative direction). Even after they fixed it so that the prior value was not added in to the current frame when you applied the collapse the movements would not look like the motion before the collapse as Poser does not fully calculate the effects each layer has. AS some layers just replace the base movement and others add a correction to the other layers. So something that was nice and smooth started to jump all over the place because of Spline overshoot.

As another issue add in more then 2 layers and then try to use the dials or movement graph when the layers are not set to replace. Depending on the level a layer has in the chart (anything below the uppermost) then the effects become unpredictable. Also in the layers menu you can state a start and end frame for the layer. Then go outside of that range make a change to a parameter and the layer expands to include that change. Causing other parameters to change their Spline movements (depending on Key Frames).

SO if your script is only going to be for a base layer only animation you might have a change. If it is used with Layers then you will have a great number of checks you will have to do to make sure it does a simple reverse.

Poser 9 had some issues but was easy to use. Poser 10 got worse and 11 even worse then that. I had hope that when the last Dev Team did a survey about 2 years ago on the SM site about Animation features that they were finally going to fix it so it works like it should (or at least how the manual implies it should work). Now that it has changed hands I have no clue where animation falls on the priorities of things to improve. That is why all they should do is make all functions available via Python.

Poser 5, 6, 7, 8, Poser Pro 9 (2012), 10 (2014), 11, 12, 13