If you are getting too many fills, either widen your envelope (but you are pretty wide already) or reduce the number of stocks you use. From what you have written it sounds like you are doing everything correctly but it is hard to tell unless you indicate exactly how you are coming up with the prices you send in. Check the fills you are getting. Were the stocks really gapping up or down? If not, maybe there is an error in your calculation somewhere. During earnings season it can get pretty wild on the OPG front, so the number of fills you are getting might be correct.