Combining multiple calculated metrics to get an average.

I want to combine PQ/5, PQ4 and PQ4 to get an average weekly. PQ/5 is purchase quantity divided by fiscal week in Jan which equals 5 weeks. PQ/4 is for months that have four weeks using the fiscal calendar. The outcome would replace PQ/AVG Weekly which is just giving me the weekly avg for April. I would like it to be the avg of PQ5 Jan, PQ/4 Feb and PQ/4 March.



