Producing Monthly Totals- tied to a calendar

I'm creating an output spreadsheet for a factory floor.
All I need is a formula that creates a monthly output figure.
I have one (column H) but it is reoccuring every four weeks and doesnt start at the start of a month, therefore within a couple of months it is not in synch with the dates in column A.

Any ideas?

Thanks for your help.

Hi.

If possible, i would like the monthly totals to link to the dates in column A, and produce a total for the last date of every month. So the may total would be on May 31st etc..
If not, then i'd like the total to be at the end of each week where a month ends. If that makes any sense?

(that was an apalling sentence, sorry)

Ideally, the april total would be in H10 and the May total would be in H40...