I don't know what in particular you're set out to do, but something that works well for me is the following. It decides one out of 14 different outcomes and it's quite random and fluid for me.
INIT
DB_DC_FTJIRandom(1);
KB
...
AND
DB_DC_FTJIRandom(_Chance)
AND
Random(14, _Ran)
AND
_Ran >= _Chance
...
