Two things: On the multiple entries, just make one entry, enter the country as "Various", and consolidate it. It works for me.
On a second matter, the tax credit calculation:
Hopefully this isn't too late, but I was having a somewhat similiar problem. The issue was that when TT imported the dividend data from Vanguard, it missed the income from the foreign entity that generated the foreign taxes. To check if this is the issue for you, go to the Forms section, and go down to the FORM 1099-DIV Worksheet. Look down at the Box 7 entry and it should show the foreign tax paid (Say $200). Then look at line "d". It should show the dividend income that generated the tax, (something like $3000). If the figure is not there, go back to Vanguard (or your broker), get the number and enter it.
In 2019, it was automatically enetered in the transfer process, for 2020 it was missed. Either a TT problem or a Vanguard problem.
Fo me, when I found the error, I had to file an amended return.
