Using timed access control in airport express Have read Using timed access control in airport extreme base station but the fix described has not worked.

Clicking "+" reverts the times back to the default "09:00  to  17:00"?

Any suggestions?
You have to press Enter after changing the time fields (so the cursors jumps to the next one). It's kind of user-unfriendly, bites me a lot of times as well.