Only 4 Siri Recent App suggestions on iPad

When I swipe down from halfway on the home screen of my iPad Air, I get the usual search screen. Before I enter any search text in the field, I am presented with 4 icons for recent apps that I have used that I can jump to quickly. On my iPhone 6, I get a choice of 4 or 8 recent apps, toggling back and forth with the "Show Less" or "Show More" link.

Why don't I have the option for 8 recent apps on my iPad?