one of my strategy is similar to market maker, that is, buy and sell order sitting on nbbo waiting for others to hit me so that I can capture the ask-bid spread. when market moves up/down, my order will also move along with the nbbo. currently my algorithm will adjust the order whenever nbbo changes. IB reminds me that my order/fill ratio is too high, and it asked me to lower down. I do not know how to lower down. I used relative order, but when bid moves down, my order does not move down with it, so it does not fill my purpose. any thoughts?