Randroll is from 1-100.
Given gmax machamp is 5%, so 96-100, and you need 1% that is before gmax machamp,
try 95 as randroll.
Also update your plugin (use the latest version). They should have fixed all of the one-off errors by now.
Also, for rare dens (purple lights), I recommend using either 2-0 or 4-1 for dentype and flag respectively.
(as per used by the base game)
In any case, it shows up fine on my plugin. (using 95 VS 94)