I'm still confused.

ok so if I buy at $500 then that means the BASE_VALUE is $500 right? So the above statement (without trailing) just adds 0.6% to $500 which makes it $503. What is it comparing that $503 to though (ask, bid)? The statement seems incomplete. I want to sell or buy when the current (ask/bid) price is 0.6% more or less than my last buy price.

This is how I'd like to see it.

ask = 620
bid = 615


If market bid price > .6% of my orders last buy price (plus exchange fee) sell amount .01BTC at Market bid Price
if 615 > 606+.02%fee sell .01BTC at 615


If market ask price < .6% of my orders last sell price (plus exchange fee) buy amount .01BTC at Market Ask Price
if 620 < 615+.02% buy .01BTC at 620