Tom,
I agree with you that in general PC should increase over time as stocks generally increase, but I don't agree about the method of this increase. Lichello increases on buys, which occurs when stock declines, and which may have worked OK for him as long as the stock takes brief enough dips and recovers.
In my spreadsheet the increase in PC proportional to product of time and a slope that may be positive or negative. The slope is small in absolute value (less than 10%) and is supposed to represent the gradual increase or decrease in the value of a stock. It's usually pretty obvious if the stock is in an uprend or downtrend over a longer time frame and what the slope is, but it may be taken as the slope of a slow moving average.
If the stock goes into a downtrend the negative slope will dampen the rise in PC-SV and making the model more stable and reducing the tendency to deplete cash too early. If the stock is in an uptrend, which should be the case most of the time, the rise in PC helps to prevent early sell off and decreases the need for Vealies. In my spreadsheet PC will increase even if the stock does not drop and there are no buys.
Adam
Market Data 
Markets 
AI
