KLM SEA-AMS

I am a little confused on the uses of FSUIPC. I am using custom AI flightplans, so do I understand it correctly that since these flightplans have a set density, and that lowering the density is therefore very difficult and takes a lot of time with the normal FS2004 Options->Traffic way. So I was wondering, from what I understand from the description of FSUIPC, it is possible to adjust the density of the AI in the Sim. Is this true and if so how can it be done?