Not to scare anyone (well, sort of as an fyi), but there was that whole controversy regarding excess bromide levels in Dowflake produced during a certain time period. The conclusion being that such changes resulted in Dowflake being "OK" to use but its longterm effect on aquaria was unknown, I believe. And as Rob mentioned, the altered Dowflake results in a lot more sediment.
http://www.reefcentral.com/forums/sh...5&pagenumber=1
The guess the bottom line is that it's not just a difference in name, but there are substantive differences in chemical mixes.