Latest iCloud backup not on phone list at restore

Hello,

My phone was recently stolen. I got a new phone and restored to an iCloud backup. However, when I click on my iCloud settings on my computer, it shows that I have an iPhone backup from 11/21/2015. When I restored my phone, this backup was not in the list of available backups, with the latest one in the list being back all the way from September 2015. Does anyone know why this would be the case? I do not necessarily want to delete everything and try again, but I am very curious as to why my iCloud settings show a backup that is 2 months newer than what was on my phone options at restore. Any info is appreciated.