Well, in my past life (work) I used a lot of computer programs in various disciplines and the old saying of garbage in garbage out is very true. I'm definitely not saying the Flow Illustrator program is garbage because it is not. I was quite impressed with the out put from it. I'm only saying it would be difficult to obtain any quantitative information not knowing the total input information and the conditions under which the model is subjected. i too am impressed with the improvement in data processing that has occurred since I first processed "data" by hand and with a hand held calculator which believe it or not was not allowed in any of my college classrooms. Ah, the "good ol' days". Yeah right