I need to top-up engine oil on my 125TSI.

User's Manual says use VW50400 for longlife service, or VW50200 for shortlife service.
As could be expected, no explanation as to what my car comes under.
Google search shows Longlife as 30,000km, so on that basis I shoud use VW50200.

Now, the questions -

Does it really matter if I use 50200 or 50400? Would it be harmfull to mix the two? How do I know what is in the car now?

Any feedback would be appreciated.

Joe