The function rand(ID) will always return the same value for any given value of ID since it's a seed value. For example, heres the first four keys - assuming you start from 1 and increment by 1:

ID          RAND(ID)
1           0.71359199321292355
2           0.7136106261841817
3           0.71362925915543995
4           0.7136478921266981

Notice that the Gaussian based random function is magnitude sensitive. What the function I gave was attempting to do was use the wider swing in the less significant digits to provide a pseudo-type randomness (the 7th and 8th digits vary between 0 and 99). By adding in the millisecond clock to these two digits, you help make it a different value each sweep through. Not exactly a nice random function by mathematical standards, but perhaps random enuf.