Webmail east vs. myemail

My husband and I have separate email addresses on Cox, both set up at the same time. When I need to look at our emails on the internet (instead of Outlook on our home computers), we go to different sites. His is on webmail.east.cox.net, while mine is on myemail.cox.net. I prefer the format used on his. Can we do anything to change mine? Why would they be different in the first place? Thanks.