That message is very approximate -- it always rounds down to the nearest time unit, so 1hr 59min from now would display as "1 hour from now" -- There's a bug report about this (
https://github.com/Extended-Thunder/send-later/issues/271), and it will be fixed soon. You can ignore that part of the message entirely if you'd like. It's only there to prevent basic accidents like sending on the wrong day, or at 10AM vs 10PM, where it might be easier to spot the difference between "2 hours from now" vs "14 hours from now", for instance.