SUMIF columns from another sheet - against a 4-4-5 Calendar

Hi everyone, first time posting on this board so forgive me if I have not done this 100% correctly.

I really need help with a sheet I have titled as 'Forecast Summary' - effectively what this sheet does is pull cost items from multiple tabs which is split as follows (see example below...)

Capture1.PNG

On the various tabs that this forecast summary sheet pulls from has each week of the year which is being split against a 4-4-5 calendar, i.e Nov-19 4 weeks, Dec-19 4 weeks & Jan 19 5 weeks... and so on. I then need to be able to copy this formula across each month, the problem being that the 5th column (Total) is an extra column within this sheet, that I dont want to add to the other sheets that it pulls from.

Effectively what Im looking for is a dynamic SUMIF formula which is flexible to a 4-4-5 calendar, and which can be copies across for approx 24 months!

Any help will be enormously appreciated!

Thanks all!!

SOrry I forgot to mention that to the left of 'WBS Activity' in the above example is a unique code, which needs to pull through from the other tabs (the SUMIF function is as far as I could get!)

Below is an example of one of the tabs the sheet needs to pull cost from...

Attachment 645349

Thanks again!!