Hello Dale,
I also have been looking into the importance of the limit value in the equation and I can't see how it is going to change the output too much. It will change the actual number value that you get, but if this is the case then as you said earlier, the "shape" of the ASI will be the same, just the values will be different. With forex pairs, since there is technically no limit, I've thought about deleting the limit altogether (by dividing it by 50 which as you said, would mathematically make it irrelevant). I have not had the problem yet of a SI value being greater than 100 or less than -100 because so far I only have it set up for gbp/jpy, which is quoted in the same format (xxx.xx) as the commodities in the book it seems. In the book, on page 89 example 15 where he says that the SI will have a max value of 100 on a limit day, perhaps the reason you are getting a value higher than 100 is because the price is moving more than the "limit" value in the equation which gives you a number higher than 100 or lower than -100. I can see how the limit value might mean something in instruments that have a limit, but with forex pairs, and gold (to which my knowledge has no limit) it is useless.
I went to the CBOT website and looked around a bit, but I couldn't find a page where it listed the limits for the commodities... what would you say are the most popular commodities? On bloomberg I see soybeans, oil, coffee, gold, natural gas and corn most often. Is the limit usually a set number or do they change it often?
Also, here's a quick summary of my current volatility system trades:
AUD/JPY short @ 96.04 +521 pips
USD/CAD long @ 1.0232 -4 pips (was as high as +50 earlier today)
Gold/USD short @ 943.85 +29.25
Because aud/jpy is a "commdoll" and since it is decently correlated with gbp/jpy, after I get reversed out of this trade I am probably going to stop trading it altogether and switch to gbp/jpy exclusively to avoid any problems. For now I'm going to keep watching usd/cad, unless I can find a pair with a higher CSI that isn't correlated strongly with gbp/jpy or gold.