I am trying to figure out a new formula. I am trying to create a maintenance
chart. There are services due on an engine at 12, 24 and 50 hours. I want
to be able to input the time used on the engine and have all the service
marks count down until they hit zero or a negative number. Once the zero or
negative number is hit, I want the service hour column to reset to the
respective number (12,24,50). What is the procedure called and what is the
formula I need to use in order to make this work.