OK so how about if we use Column O to determine which rows are subject to the filtering.
So in Column O we can use something like =IF(M1>N1,"FILTER","") This will show FILTER when the value in Column M is larger than the one in Column N. Then we can filter on Column O and we are done!
This technique is called "making a helper column" we use a column to give us what we need and since we have plenty of columns (16,384) we can afford to do these kind of things. I have not seen any worksheet consuming 200 columns let alone 16K+. Also you can use ANY column as a helper column, it does not need to be Column O, but it is nice to have helper columns near the dependent columns. You can also hide these helper columns so that they do not interfere with the "looks" and design of the worksheet.
Hope this helps!