I'm a native North American and I too don't understand "the weight of a box of smarties".
Sorry about that, I just happened to have been munching on some smarties
I suppose I could have used the idiom - 'hill of beans', Or more precisely the difference in weight would be about a tablespoonful of beans.
Actually you guys seem to have already got it - I am glad to see everyone agreed so quickly, but there was just too many words and much time spent complaining about something so insignificant. So many 'issues' that just are not issues to anyone with more than a 1/4 brain. It's almost like some people just 'get off' on complaining so they make up this fantasy universe where those small changes are really significant issues.