Changing your pitch will change your tone and yes you can do that in FL, you can also change velocity in FL which is something that I do on every song that I make. Changing your velocity on certain instruments like drums really brings them to life, it takes away that DIGITAL feel and gives it a more REALISTIC feel. Velocity is pretty much the power or strength of a hit...for example, on a drum machine, each individual snare hit will sound exactly the same as the one before making the entire snare line sound like its digitally reproduced whereas, by changing the velocity on each snare hit will add the human error factor to it making it sound more realistic. A human drummer cant reproduce the exact same hit each time on a snare drum, kick drum, cymbal or hithat either.
Most producers use a kick that just sounds good to them but some producers use a tuned bass kick, one that actually matches the pitch of the song. That is what skid is refering to. His fomula will work on any instrument but the formula isn't 100% accurate because of the way sharps and flats work, which means you have to make adjustments to compensate. You gotta remember, this is just a tool to get you close, it's not the perfect answer. Just think of it as another option to using your ears to tell you what is sonically correct.
Its not about changing your pitch to .5 he's saying .5 = 50% or half...in other words if you come out with an answer of 84.4, 84.3, 84.2, 84.1 then you round off to 84. If your answer is 84.5, 84.6, 84.7, 84.8, 84.9 then your answer is 85.