Cumulative sum formula

Originally Posted by Andrew-R

Your formula would correctly calculate the first transactional value at £30,000, but then would put the second at $30,275, because it would add the value of the 1st 100 transactions to the 2nd single transaction.

And that's how I understand cumulative SUM...
But also we have now Marcol solution that also have sence...

Now we only need to wait and see what user expect as result.