How to read and use getServerTime()

There should also be getServerTimeOffset(). That one gives you the difference between server time and client time. Both, getServerTime(), which gives you the absolute serverside time and getServerTimeOffset() are there to offer you an authority on the time, when a client for example sends something like "do that action seconds in the futuer from the point of ime, when I have triggered it", as the receiving clients local time could differ by relevant amounts from the one of the sending client.

For measuring the delay of messages, you should either use getRoundTripTime(), which basically is the ping of a Photon command or in case that you need the overall delay of a message on high-level, no matter he low-level details like if parts of it had to be repeated or if it has been split up into several chunks, if it has been hold back in a queue for a while, because a client did not want to sent o receive it immendiately, etc., than you would let the sending client, which for example calls opRaiseEvent(), put the returnValue of getServerTime() into the payload of the event to raise and on the receiving client you would read that value out again and subtract it from the returnValue of getServerTime() at that moment.
The difference between the both returnvalues of getServerTime() will tell you, how much time has ago the message has been sent.

The 7 hours by the way is the time, that has passed, since your server has been started modulo aprroximate 49days.

Could be missing in Flash.
It's not really needed when you use getServerTime(). The offset is not valuable by itself, cause getServerTime calculates the server's time (using the offset) for you.