It seems as though Disney is testing allowing guests to book 4 FastPass+ reservations using the My Disney Experience app and website. This is expected to be a limited-time test over the next couple of days.
As shown in the screenshot below (from Spot Mickey's post on Twitter - https://twitter.com/SpotMickey/status/582178127184543744), 4 reservations have been made for Magic Kingdom today, and also for DHS on Tuesday...
If Disney decides this test is sucessful, it would certainly improve the FastPass+ system!