Joking / Kidding

Reading an interesting article today, the last part of the article caught my attention. I know we, as Malaysians, are using British English, because we were once being colonised by their country. However, I never know that JOKING is British English and KIDDING is American English.

(BrE) = (AmE)
bill (e.g. for restaurant meal) = check,
flyover = overpass,
full-stop = period,
groundnut = peanut,
maize = corn,
petrol = gasoline

I wonder if I am writing my SPM English paper now, will it be marked as a mistake when I put overpass instead of flyover or peanut instead of groundnut. (Do you use 'groundnut butter' or 'peanut butter'?) I still can remember we were always being corrected when we write COLOR (AmE), APOLOGIZED (AmE) etc.

Russians are using American English, so it's quite confusing when I shifted here the first year in my university. However, it's not much a trouble as I am studying in Medical Faculty and not English Language Faculty. =P

Do the examiners really define which words are of British English and which are of American's? or they don't really know it well? Today's world is so much being influenced by American's culture, how can we really separate BrE from AmE?

I guess language is a pretty difficult subject to go deep into UH~~. =)