It looks so simple according to the documentation. Select your graph windows, save a copy, choose .xls in drop-down menu.... But the only options I can see in the drop-down menu are .mrs or .mrp
What's up doc?
This is probably a windchill / PDM system conflict. Are you using windchill / intralink? Can you try outside of that?
Here is some PTC help on the saving of simulate results. I do not have windchill so I cannot help much. I used Intralink PDM about 20 years ago, so I have a tiny understanding of PDM.
I also found this that says you can export the results out of your workspace and that you can only choose the option to vault results if you are working online with the PDM system and have the part checked in. So from this maybe check the part out into your workspace, or even work offline and see if more or less options to save appear.
I have a suspicion that since you were not aware of the PDM that you do not know the workspace, check In/out process yet. Chances are if you have PDM that you have several others at your organization that know how to work in the PDM system, and you can reach out to them to give you a demo.