Hi David, and welcome to the forum!
Can you give us some more information about what the layout is of your spreadsheet, and how the cells interact? You talk about late/accident and dates, but we have no idea where that information is, or in what layout (rows/columns, diagonals
)
Is there a due date or something? Perhaps you could even upload a sample workbook, showing what you have, and highlight where you want a formula to go (and the value you want to see)