determine correct cell and color based on four parameters.

I need a macro or series of macros to determine the correct cell and then color to return a number for a product. In the attached file the correct answer would be D5. The parameters in M5-N7 determine what part of the table to look at then I need to find the closest number to N8 in the chart without N8 being larger than it.

So, it should be looking at D5:D6 in the table then D5 would be the correct answer. But i am unsure how to do this in a macro or formula for the entire chart.


Thanks in advance for any help.