What to do when you notice that a value in your paper is wrong, once it is accepted but before it is published? 8 months ago, I have submitted my paper to the top journal in my field and finally it got accepted. Unfortunately, I have found one wrong table entry (Experiment Section), which is not a logical value at all. More precisely, I was copying from my raw data (in cm) to the paper (in mm) and I forgot to convert one value. Actually the mentioned value is not possible at all and the change does not affect the conclusion of neither the corresponding subsection in the experiment section nor the conclusion of the paper. This paper is very important for my PhD which will take place in few weeks. 

I am pretty sure that reviewers did not deeply examine that table, otherwise they would find out the error because it is too obvious. Now, I am wondering how to deal with this issue. 

Ps. Another problem is that in the policy of that journal, the paper which needs another major revision will be rejected. Now, I have one week to provide the final revised version.
This is not a major revision. Just change the value in the final version. (And explain to the editor in the cover letter that you are correcting a typo. A misplaced decimal point is essentially a typo.)

You are not misrepresenting yourself in any way. Because you're explaining the change in the cover letter, you are giving the editor the chance to reject the paper if they deem the changes are big enough to count as a "major revision". However, any editor that rejects the paper for that reason would have to be totally insane. Typos get fixed in the final version of papers all the time.