Hi Christine,
As far as know if you select any dimension either row or column or page axis then you can not use same dimension in other axis. For example i have selected time in page axis then i can not use time in column or row axis. you can link the dimension members using property but you can not select same dimension in both axis.
for you case instead of using page axis simply use epmcontext member with filter so it will show only parent level members for selection and the use dimensionoverride. Take look at below screen shot.
For time override i used C6 cell.
Hope this will solve your problem.