Variation in length of MSc studies I have acquired a 4 year BA degree in one of the social sciences. At the moment, I'm considering applying for MSc outside of my country (I'm Non-EU citizen and I will apply for MSc studies in EU country).

The University where I want to apply has 3-year BA programmes and 2-year MA/MSc programmes. However, in my country I finished a 4 year BA programme with a total of 240 credits and MA studies are usually with a duration of 1 year. I really don't want to study 2 full years for something that I believe I could finish in a considerably shorter time (one year). Also, I already have the necessery credits for the first year of the MSc programme.

I would like to know how is this handled? Does the number of the acquired credits I have matters, or is the official length of the MSc programme that counts?
This is not a universal truth, but my experience in researching Master's Programs is that the main difference between a 1year and 2 year Master's program is the research component. 

1 year programs tend to be primarily course based, with a shorter project, if any. Very seldom will there be a 2 year program consisting entirely of classes. Instead, there is usually a thesis, project, essay, etc. that can last around a year. 

No matter how skilled you are, research takes time. So a 1 year Master's program will necessary mean a more shallow project, whereas a two year program alloes for more depth, and is more likely to result in publishable research.

So when choosing a program, ask yourself what you're trying to get out of it. If your main interest is classes, 1 year is fine. If you want to be a researcher or tackle an ambitious project, 2 year will probably be better.