If the latest "TV Listings" on tvguide.com can be believed, it appears that the 8:00PM Wednesday airing of BB15 will remain in place, as "The American Baking Competition" moves to 9:00PM and stays there after the 26th.
soooo... AFAIK, the BB15 viewing schedule is Sunday 8:00PM, Tuesday 9:00PM, and Wednesday 8:00PM, starting June 26th, till further notice.