I will be submitting a conference paper that proposes a new method for analysing a particular kind of data within the next 2 weeks. However, I think that I may improve the method slightly during the following 4 weeks that the reviewers use before giving feedback. The improvements will be minor, but it would be nice to include. It is out of the question to wait with submission for another conference based on this potential improvement.
Is it okay to simply replace the old results with the new results if the results improve after submission? More generally, how much can one add to a conference paper after it has been submitted? Is it only allowed to add elements that the reviewers request?