2 * .8x * 10% price change where x is each 10% interval.
Doesn't 2*0.8x*10% just simplify to 0.16x% ?
I'm kind of surprised it's that straightforward, but I suppose you are taking an overall trend.
Are you saying the price change is linear with respect to x, so it charts as a straight line? Or am I being stupid (quite likely) and missing something?
I thought it was just an example, there could also be a separate set for X such that f(X) = current_volume * k?
I think volume change might have little affect on the actual price compared to depth of orders... You could instead look for an exponential run up in volume maybe?