I did my 3 rounds (All VCs) and all technical questions. (They never asked me why!)
It really depends on what position you are interviewing..
Frankly, for Quant Side, most of the directors like to shot the hard tech questions..Becuase most of them are from the similar path, so they may not care about the story.. (i.e. Engineering to IB or Science to IB)..
As there will be 3 persons, certainly, there will be some hard technical questions ahead. And I would expect the questions will be more difficult, since most of the European people are more technical.
Anyway, just be yourself. You can always get what you deserve. it's a fair game