标题：为何有时发单的价格很不合理，有时为0？

DATABASE('Provider=Microsoft.Jet.OLEDB.4.0;Data Source=D:\test.mdb');
DBTABLE('Select * From pursueextrem where stockcode = "IF"');
mark:=dbvalue('remark');   //从数据库中取值，用于标记之前是否有下单

//------------------------------开仓设置-------------------------

dk:=c>(ref(llv(l,80),1)+habove) and mark<=0 and tisprvremain(0)=0;
kk:=c<(ref(hhv(h,80),1)-habove) and mark>=0 and tisprvremain(0)=0;

//-----------------------------开仓下单---------------------------
if dk then
BEGIN
    if mark<0 then
    begin
        tsellshort(1,lots,mkt);
    end;   
    tbuy(1,lots,mkt);
    DBEXECUTE('update pursueextrem set remark=1 where stockcode = "IF"');
   end;
if kk then
BEGIN
    if mark>0 then
    begin
        tsell(1,lots,mkt);
               
    end;
    tbuyshort(1,lots,mkt);  
    DBEXECUTE('update pursueextrem set remark=-1 where stockcode = "IF"');
end;
if tsubmit(1)>delay or tsubmit(3)>delay then
BEGIN
    DBEXECUTE('update pursueextrem set remark=0 where stockcode = "IF"');  
 if TSUBMIT(1)>delay then TCANCEL(1,1);    //开仓单120秒后未成交撤单
 if tsubmit(3)>delay then tcancel(1,3);
 end;

mark:=dbvalue('remark');   //从数据库中取值，用于标记之前是否有下单
//----------------------------------平仓-------------------------------------
//持多仓阶段的止损止盈

if mark>0  and tisprvremain(1)=0 then      //mark>0 and tisprvremain(1)=0代表多单挂单成交
begin
   if c>=(TENTERPRICE+zyd) then
   begin
     tsell(1,lots,mkt),ALLOWREPEAT;     
        DBEXECUTE('update pursueextrem set remark=0 where stockcode = "IF"');
                   
   end;
   if c<=(tenterprice-zsd) then
   begin
     tsell(1,lots,lmt,tenterprice-zsd-hd*mindiff),ALLOWREPEAT;     
        DBEXECUTE('update pursueextrem set remark=0 where stockcode = "IF"');
               
   end;

end;
//持空仓阶段的止损止盈
if mark<0 and tisprvremain(3)=0 then    //mark<0 and tisprvremain(3)=0代表空单挂单成交
BEGIN
   if c<=(tenterprice-zyd) then
   BEGIN
       tsellshort(1,lots,mkt);
       DBEXECUTE('update pursueextrem set remark=0 where stockcode="IF"');
       end;  
   if c>=(tenterprice+zsd) then
   begin
       tsellshort(1,lots,lmt,tenterprice+zsd+hd*mindiff);
       DBEXECUTE('update pursueextrem set remark=0 where stockcode="IF"');       
   END;
       
end;