How to add values only up to a certain number?

Hello! I’m trying to work on a table that’s going to track the baseline hours (90) and extra hours. There are two separate tables that track clock in and clock out times, as well as the number of hours worked for both employees.

As it is, I’d like the cells B2 and B3 to work on the condition that the maximum amount of hours is 90, shared between both of them. And that, after the counter hits 90, that it should instead start showing the remaining hours in the “extra hours” rows. It doesn’t necessary need to split between both employees like it’s showing, it’s okay to be one single cell tracking both.

Is this possible? Or is there a much simpler way to achieve what I’m trying to do? I’ve been staring at this for a long time, so forgive me if I’m missing something incredibly obvious.

Thank you kindly!

[Edited by Moderator]