Chinchillas prefer being in their cage?!

I recently upgraded my two chinnie's home to a cage literally twice the size, with lots of toys, shelves and space to leap around.



Previously they couldn't wait to get out their cage and would never go back in when their play time was up.. Now that I have upgraded their home they never want to leave it and when they do come out they only stay out for around 45 minutes before they go back home. Should I be concerned or do they just prefer their awesome new home?