Yes, the statement is correct.
Whatever level pagetable, the pagetable entries refer to main memory frames. So, the number of bits in pagetable entry doesn't change.
If a pagetable is not fit in a page, we have to divide the pagetable again into pages. To maintain pagetable pages we need another pagetable. If you want to run a program we need to load into main memory including pagetables. The pagetable pages also will reside in main memory frames. So, the entries will refer to main memory frames.