It sounds like it should work from what you’re describing, but perhaps there isn’t enough flexibility in those value to get it to the bottom of the frame? If you Shift+Click on the Justify button, does it work?
I’m familiar with the bug that prevents InDesign from applying vertical justification if there are dropcaps on the page, but V-Justify definitely works in this case and is not affected by dropwords.
If shift-clicking doesn’t work, I’d be happy to take a look at your file and see if I can figure out what’s going on. So feel free to send me the file.