Japanese to English size estimate always wrong

I think your calculation for a typical translation size is always wrong for Japanese to English. You should know that 10 Japanese characters will typically translate into 20 English words. EVERY time I translate Japanese to English, I get this message:

The size of your translation doesn't match the size of the source text.

I think you will see the same problem from Chinese and Japanese into almost all languages.

I know this problem it happens very often on short translations. We have a page of language statistics here that are computed from the accepted translations.

The warning uses this ration to decide if it will be displayed or not. Next time it happens, could you copy paste here the source text and the translated text in order we can see if it's a bug or not ? Thx.