Buying one license

Good afternoon. We are now at "Tariff-5" with 5 licenses. In fact, 5 people work for us, but a couple of times a week an evil accountant comes in who needs to see some data from Boxing and it turns out that he becomes "sixth". That is, some manager has to exit the program, free up space so that the accountant can get acquainted with some data. It is very uncomfortable. We would have bought an additional license a long time ago, but as we understand it, there is a Tariff with 5 users and the next one already with 10. We certainly don’t need 10 licenses, we are still small, and 5 are not enough. What option do we have to let 6 people into the box at the same time? How to buy one license instead of five? The task is very simple and I am sure that the administration can solve our issue with a "click of a finger", the question is in the will. What options do we have besides switching to "Tariff-10"?