I would like the ability to manually change the status on time tracker feature

I invoice for my time (thru a desk top version of Quick Books) before I start a project. I track my time, and once I hit 20 hours I start billing by the month. I like to keep a track of total time on the project, but I would also like to be able to see next to each entry what has been paid for and what needs to be billed. So to have the ability to adjust the status manually would be great