Sorry Don. The principle of using a second word to count the second beat of a slow is fine but the word AND is already defined as meaning half a beat stolen from the previous step, as KC mentioned, and this applies to standard as well as latin.
Phil; the idea of using two syllables when counting Slow is useful because it generally takes no longer to say Slow than it does to say Quick, so it is very easy fro the difference to disappear.
Our preferred alternative is to count slow-ly, quick, quick, or when exasperated by dancers rushing the steps, Slow-er, quick, quick.
Note, I'm sticking with the standard 2,1,1 timing here. Anything else can come in private lessons for advanced dancers.