max date per metric - with differing max dates

[#1]

Hi I have a table of metrics - some have different max dates.

For my report I wish to show the most recent data for each metric

so for example some may be for Aug 13 and others may be for Oct 13.

My formulas is -

sum(numerator)/sum (denomenator)

Im also needing for each metiric to show a 15 previous month chart based on the max date

Pls Help

[#2]

Anyone able to help with this?