Random Pokemon Encounters?

[Kaichu]

::Random Pokemon Encounters
:::Wild Pokemon you encounter while in tall grass are completely random. It can range from 1 to 493.
DB000000 021D15A8
421D15A8 7FFFFFFF
D4000000 00000100
D0000000 00000000
D7000000 022186D4
D2000000 00000000
622186D4 00000000
322186D4 000001EE
DA000000 022186D4
B2111880 00000000
C0000000 00000027
D7000000 00025A68
D2000000 00000000

I've been trying to use this code, and it doesn't do what it says it does.

It does change which Pokemon you can find in the wild, but it isn't random for me at all.

I've found the same code on this site, as well as a few others, and I've triple-checked my input.

Am I doing something wrong, or is the name of the code just misleading?

Thanks in advance.