Ok, to skip the same amount of time for everyone in a mp game the first thing to do is:
1. Make a trigger on the map (I call mine server)
2. Create a global variable (in init.sqs) for the time to skip to.
3. In the time jumping script have the first line be
?!(local server):goto "client"
4. After this line, only the server performs the task, so set your global variable to whatever time you want. Then make it public (ie. PublicVariable "variable name" )
5. Then change some other variable to let the clients know the server is finished.
6. Make a client tagline (ie. #client) and start it off with a @variablename (for whatever variable lets the clients know the server is ready)
7. use your skiptime command with the publicvariable of what time you want to skip to...
There you go, that should work for you, if not I have a script in my mp mission that does this already. I don't have access right now (I'm at work), but I can attach it here if you really need it....
Cosmic Evolution