Formula to sum by month, quarter, year

Hi All,

I have a spreadsheet which contains multiple tabs and is uploaded into another system. The contains information which shows for each month, quarter and year. Currently the sum for each quarter and year is manually calculated. Given the large data set, and number of sheets which get uploaded i am wondering if i can use a formula to automatically calculate this for  me. I have a sample attached of monthly data, with the formula's and how i sum currently. 

If there are any suggestions to improve this process to make it more efficient and easier to use going forward, please let me know. Appreciate any insight/ideas.

Kind regards,