Counting incidents in each month and updating ajusstments for piror months late entry

Hello guys,

a bit of a problem i have run it which i cant solve using pivot tables....

i have the sheet attached for review.

i get reports every month, and each row has a unique ID and completion date.

i pull report every month.

sometimes the completion date is in prior month (which will be entered as prior month) but will show up in current month report.

for eg....
a pid was completed in january by not reported until march....hence i want the sheet to show adjustment of +1 (count) for january, feb....and will display total of march only...

i have attached the sheet....

the main worksheet is dynamic and existing data will remain and new data will be added on a daily basis. so when i count for a given month - say feb....pivot table will show me cumulative of all feb....but i need them broken into months....as to when it was updated...

if the data in the sheet is not sufficient...i can extend the scenario over 4 months of how the sheet would look and how the outcome should look....


any support will be appreciated.....thank you...