Inventory report - Cumulative balance

[cognos05]

Hi ,
We have a fact table which has inventory movements data in fact and surrounded by dimension like product customer etc..

Not sure if we need to join time dimension which is at day level to the fact table because we would like to see the inventory at the end of specific period which should do a cummulative total  from the inception .

Example the inventory for July 2020 should take care of all the movements from inception July 2015 till july 2020.

Any suggestions or existing post that discuss about this use case for inventory reporting in cognos data modules .

Thanks