Logging and performing mathmatical calc. during run? Is it possible using the new EV3 to log data, and peform mathmatical calculation on the data while it's being logged, and peform some and thereby trigger some event if some value has been reached??

As far i can see, it is possible doing seperatly..
Instead of using the datalog block from education version, you can create a custom version using the file access block. It's a bit more difficult, but more flexible...
You won't be able to directly use EV3 datalog management, but you can structure the file to be directly compatible with csv format, readable by spreadsheet programs.