With respect to the data that you have shared, please share how did you arrive at the numbers 0.6,0.7 and 0.8. Please share the actual numbers that you want to see in that column with respect to the data that you shared earlier.
Let's divide the solution into two parts. First is to get the monthwise highest average DFFAM (see screenshot below). Is this result correct. If it is, then let me know and we will then get the Registry as well.