I did a gmail import, I recoped 3018 email but it lacks a lot of email.
There is no import option for Gmail. How did you do that?
If you mean you setup a Gmail account, that is not importing. If some messages have not synced, you can right-click on the All Mail folder and choose Properties > Repair. See if that helps.
It may also be that the message count differs from the server because of the Conversation mode. 4 messages grouped as a conversation will only get a single count. Disable that using Menu > View > Conversations, and see if there is any difference.