Limit of iTunes RSS Feed Changed?

(I couldn't find an accurate category of iTunes Search API..)

I got result successfully by the following url.

https://itunes.apple.com/jp/rss/topsongs/limit=300/genre=9/json

But, recentlly, it returns "Invalid value for param 'limit'".

I adjust limit param to 200, then I could get it.

https://itunes.apple.com/jp/rss/topsongs/limit=200/genre=9/json

so, limit of feed was changed..?