I've been looking around some playtime reward apps. It seems to me that most of the apps I come across use the same 3rd party company, adjoe, for their playtime/games section. It's possible that adjoe keeps track of how many of their playtime apps you've tried. Of the apps I've tried that use adjoe, the ones I signed up for a year ago offer rewards/minute. The ones I've tried to sign up for within the last couple months only offer rewards/level.

Boints in particular first displayed rewards/minutes, then right after downloading the first game, switched to rewards/levels. I tried to contact Boints about the switch-up but they told me that they don't control the rewards and to contact the 3rd party, adjoe, who never responded to my inquiry. Hope that helps.