I'm implementing DirSync using Azure AD Connect utility to link existing domain accounts to their existing Office 365 accounts. I've set up the UPN to match the Office 365 domain suffix. As I understand it domain users can still login to their PCs with their standard .local user account in addition to the UPN but SHOULDN'T they login using "username"@xxxx.com instead of their .local account in order to follow same-sign-on standards?