Cannot get all updates from iTunes software

Hello. There is a strange problem.

Sometimes, when I open iTunes from my computer, a small number will be displayed after "Apps".

When I click the "Apps", I can also see that there are some updates available from the bottom link text.

But after I click that bottom link, I cannot get all programs which need to be update listed. When I update all listed, iTunes still says there are some apps to be updated, but when I click that bottom link, only a text "No updates are currently available. To check for updates for another Apple ID, sign in with that Apple ID."

At that time, I can get all updates from my iPhone - Apple Store. So all have to do, is update all apps from my iPhone and sync it back. But if some apps are not installed on this iPhone, I have no way to update it.

BTW, I've tried to click Store - Check for available downloads from iTunes on my computer. It's useless in this case.

Any solution? Thanks.