I tested a free version of Sign-up Sheets and did not repeat any reported issues.
I will contact SS plugin developer about getting a copy of his Pro version.
Btw, I suppose that if SS Pro uses custom post type then if you turned ON “Activate “Create” capability for posts/pages/custom post types” option at “Settings->User Role Editor->Additional modules” tab, then role should have ‘create_xxxs’ capability, where ‘xxxs’ is a custom post type, like ‘create_signup_sheets’. “Add New”, “Add Sheet” buttons will be unavailable in other case.
