Hello Raymond,
I have implemented the solution in order to prevent data loss.
If all empty earning fields are filled then the system will ask
"are you sure you want to submit without Add TTMEPS checked!"
If clicked on cancel you can check the checkbox of TTMEPS in order to update the TTMEPS.
If clicked on ok then the form will be submitted without giving an option to check the TTMEPS checkbox.
If any field which is empty is left empty system would not ask confirmation message.
Please check the follow and let me know if it is good or we can alter it. 
It is implemented the same way as you suggested.  