This is a feature which should have been there since the beginning of Office 365; you can now define a time zone, as well as a secondary language, when you open a support request on Office 365.
This does not seem to be a huge improvement but talk to people working in a multinational with a tenant hosted in a different time zone – with this feature, no more call in the middle of the night because you are based in Asia and your company has created the tenant in Europe.
To select the time zone (as well the optional secondary language) just logon to your Office 365 administration portal (https://admin.microsoft.com) and open a new service request.
Then as always follow the initial wizard/self-help solution and then choose Contact support at the bottom of the blade; after filling the details of the issue, scroll down the blade and look for the Regional Settings option.
The time zone you define the first is saved, so you should not have to set it again the next time but, you know, always worth checking before