The cumulative totals of the dummy 1099-Divs and and the reduced amount on the original 1099-Div in Turbotax should equal what is reported on the brokerage form. I have never had an issue.
For example, lets assume the broker reports $2,500 of foreign dividends on the 1099-Div. There are $750 from Canada, $650 from Brazil and $1,100 from Germany. Lets say each are entered into individual Dummy 1099s, the total of the three 1099-Div form should equal $2,500.
I hope this helps.
