I believe that it is important to remember that the rating system imposed by each country is based on the major ruling social, religious and political factions.
Don't get me wrong, I am all for the rating systems as they are presented however don't forget that they are a guide and a guide only.
It is your decision as parent who knows there own child's level of comprehension as to what is suitable for them to see or do.
So as old Obi-wan told us, "You must always do what you feel is right"
Also the rating is applied to use of the product so it could be an issue of a younger kid getting frustrated that they can't complete the game or just get bored with it.
This is why I know my son at 3 1/2 will be in the Toy Box in simple maps that I make for him.
Just my 5 cents.