The bacteria found in these various "dry" septic tank products do not contain nitrifying bacteria. Having said that, the non-pathogenic heterotrophic species of bacteria that are found in these septic tank products can definitely aid in nitrification by reducing ammonia & nitrite levels. I know this for fact as I used them to do just that close to a decade ago when setting up some new tanks. Here's a good read on the subject which explains the difference in the various bacteria.
http://www.bioconlabs.com/autoheterobac.html
I believe that Seachem states that Stability contains "some" nitrifying bacteria, and IME it works quicker/better than simply using "dry" septic tank bacteria. Of course some established filter media will also get the job done, and if/when available will cycle a new tank instantly.