Returning Date based off Value

I have a working formula of my attachment for reference. In the Working Example tab you will see that in column G a date is returned based off the values in F. Based on the inventory value column G will show the last date that I will have enough inventory.

I took the formula from the working example and tried to convert it into my report but it wouldn't work. The Data Set tab is the actual format of the data I work with. The Summary tab is where I will need the date to be reflected just as it is in the Working example tab.

Any help is appreciate. Thanks