This reminds me of a video I took of my two that I couldn't resist not sharing.
https://www.instagram.com/p/BLq7MiBh...ttie.and.casie
Maybe it's a matter of sleeping style? The beds I have are the same size and seem to be a good fit for my two (but I'd definitely go bigger rather than smaller in terms of bed size). Casie seems to always hang her body off the bed or sleep to the very edge of the bed, while Scottie likes to be contained within the bed. Though I'm pretty sure even Casie curls up at night when she sleeps.
But maybe for Deuce, it's colder at night so he curls up? And during the day, he's just 'lazing' around, so he's sprawled out?