Assuming your tests are accurate, I'm not completely surprised you still had 0, 0, 0 in a completely new 75gallon tank, after days. This could mean you just didn't have enough source of detectable ammonia. I don't think the bottled BB had anyting to do with, yet, if Nitrate was also 0.
The last two tanks that I cycled (in different periods) were both basically 260 gallons. Both times I used Stability. The first tank took nearly 2.5-3 months to cycle! I suspect because I didn't create enough source of ammonia relative to the size of the tank. EDIT: I tested regularly and never saw traces of Nitrite in the first tank. At one point I had 0, 0, 5ppm, and called it good.
This second time I tossed in a couple of raw shrimp (in sump filter socks), and the tank cycled in 6 weeks. I know for sure that the ammonia source is a key variable here, and likely influence the cycle time. If anything, the amount of Bottled BB, was fairly consistent as I just followed the directions the same way in both cases.
As this isn't a controlled environment in anyway, I do wonder how much the bottled BB helped speed up the cycled process. That is, would it have even taken longer in the cycled tank if I didn't have it? I will continue to use bottled BB, because I do think it will help. Just don't really know how much it does in terms of building a BB colony in less the time.
If anyone has results of such controlled test, I'd be interested.