"Finances" randomly jumps around (e.g., to "Extravagant") nearly bankrupting me

This happened so many times that I now pay special attention to this. And now suddenly mid-month my finances jumped again to Extravagant after a mechwarrior hire.

With bad luck and a tight budget this could have been game ending.

Anyone else see this happening?

Is there a way to change Finances rate mid-month?