Membership Plugin, How to increase page limits while setting up levels?

I have purchased the membership plugin. My site contains above 80 pages.

I want the visitor user should have access to most of the contents (above 60) pages and only few pages should have restricted access.

I am creating a visitors role for this, who should have access to above 60 pages but while setting up levels I can select only the recent 50 pages. Also If I add a new page the the last page from selection gets removed and user can't access it.