As expected would not quite be as advertised. I bought the bottle good for a 30 gal tank but actually used about 1/2 each in two different tanks. My normal practice when setting up a new tank for some number of years has been to use a combination of media, substrate and decor from cycled tanks combined with plants from my excess plant bin to instantly cycle a tank. By this I mean I am using enough seeding and live plant help that the tank can be fully stocked as soon as it is set up. To be on the safe side I usually dose some ammonia and test to male sure the tank is indeed good-to-go.
However, last year I was setting up a tank to receive wild caught Altum angels. To do this properly, I could not use media from other tanks. I could not risk having other bacteria or "germs" coming in from another tank as newly imported wild Altums would quickly succumb to any nasties. So I needed to set up a new tank and get it cycled without using stuff from other tanks. Even the plants I used in the set up went through a bleach dip.
My solution was to use DrTim's One and Only and his ammonium chloride to do the fishless cycle with a jump start on a 29 gal. tank. However, since I was only using half the bottle I did have to get the bacterial colonies up to strength by finishing up fishlessly. This process was further lengthened by the need to drop the pH to about 6.5 after the tank was fully cycled for 7.1/.2. This took an additional few weeks.
The second half of the bottle was used to cycle a 2nd 29 gal about 6 weeks later which first served as a Q tank for corys and tetras and now is a growout for L450 fry. That tank cycled more rapidly- if I recall in about 2 weeks which is about double the time the whole bottle is advertised as taking. So I would say it worked pretty much as advertised when used at 1/2 strength.
Dr. Hovanec maintains if you follow his directions for getting a tank up and fully cycled fishlessly, that you should be able to have a tank good to go in 5-7 days. I have no reason to doubt this.
As for the API stuff. One thing put me off, and this is their claim that their product can be kept room temp for a few years and will still work fine. I do not believe this claim and therefore I do not trust their product. I do not use Stability since it contains no live bacteria nor any of the autotrophic bacteria bacteria we want in tanks long term.
Finally, I am in the camp which believes that 1-2 ppm (3ppm max) dosing of ammonia is sufficient for a good fishless cycle and that daily dosing is not needed as well. I also am in the camp that advocates never letting ammonia or nitrite levels exceed 5 ppm.
IMO there is a very simple way to know if a tank is cycled, it is the same one mentioned often in this regard. Dose 2 ppm of ammonia into the tank. If in 24 hours you can test 0 ammonia, 0 nitrite and your nitrates have risen (save in a well planted tank where the nitrates may be consumed by the plants), then you are cycled. In fact, I normally test in 2-3 hours. Often I get the 0s then But if not, I test again in 12 hours. I have never had to test beyond 12 as I seem to have good enough results that all is clearly OK at that point. However, I would say the acid test is that this all happen w/i 24 hours- fewer is a bonus.
As for you situation, it is hard to tell what effect the API product may be having due to how your are doing things. What I can see is no increase in nitrates- usually a sign the cycle is not moving much. Also- there is a huge difference between 2 ppm and 5 ppm of nitrite. One should result in water changes to bring the number down and the other should not. I am a big fan of Dr. Hovanec. I would suggest you read the short version of fishless cycling on his site here
A Quick Guide To Fishless Cycling click on the link after the short version to see a much more detailed information about the process.
I should also say that some folks here are not fans of Dr. Hovanec. However I suggest you decide for yourself rather than trusting just my opinion or anyone else's.