NoI'm sure that it took me about 20 hoursI went with Roche (This time I'll go with Iorveth)
It's dubious. Does the game on 360 show how much time you have spent in it? are you sure you have completed all quests/monster quests? They all covered in the manual, you can check it.
Because no way it's possible to complete the game doing _everything_ in 20 hours. It's easy to miss quests though, there are some not obvious/hidden ones.
you can do everything in like 25-27 hours IF you rush.