FileOpen(): add data to an existing file ? (previous data are lost !)

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The reference ( https://docs.mql4.com/files/FileOpen ) of FileOpen says:
If there is a need to add data to an existing file, it must be opened using combination of FILE_READ | FILE_WRITE.
So I use
hfile=FileOpen(filename,FILE_READ|FILE_WRITE,"\t");
to add data to the existing file.

But, if I re-launch my script, the previous data in the file (BarS1.txt) are lost.
What's wrong in my script?
How to keep previous data if I re-launch the script?
Do you have an idea?

Thanks.


CntBarOut.mq4

//------------------------------------------------------------------------------
int i,m,n,r,s,u,v;
double indA;
int PeriodMM=11;
int ModeMM=MODE_LWMA;
int PriceMM=PRICE_WEIGHTED;
//------------------------------------------------------------------------------
//  SCRIPT start function                                                      |
//------------------------------------------------------------------------------
int start() {
  int CntBars=Bars;
    int Mode,Price,CntBO=0,sumVolat=0,hfile;
    string filename="BarS1.txt";
    double delta=0;
    FileDelete(filename);
    hfile=FileOpen(filename,FILE_READ|FILE_WRITE,"\t");
    if(hfile<0) {
        Print(filename," OPEN Error: ",GetLastError());
        return(0);
    }
    FileWrite(hfile,"Paire","Mode","Price","BarOut[%]",
    "DisM[Pi]","All","VolatM[Pi]");
    for (i=0;i<CntBars;i++) {sumVolat+=High[i]-Low[i];}
    //
    for (Mode=0;Mode<4;Mode++) {
        for (Price=0;Price<7;Price++) {
            for (i=0;i<CntBars;i++) {
                indA=iMA(NULL,0,PeriodMM,0,Mode,Price,i);
                if (High[i]<indA) {CntBO++;delta+=(indA-High[i])/Point;}
                if (indA<Low[i]) {CntBO++; delta+= (Low[i]-indA)/Point;}
            }
            FileWrite(hfile,Symbol(),Mode,Price,100*CntBO/CntBars,
            delta/CntBO,delta/CntBars,sumVolat/CntBars);
            CntBO=0;delta=0;
        }
    }
  FileClose(hfile);
    return(0);
}
//------------------------------------------------------------------------------
 
Try to use FileSeek() , for example:

//------------------------------------------------------------------------------
int i,m,n,r,s,u,v;
double indA;
int PeriodMM=11;
int ModeMM=MODE_LWMA;
int PriceMM=PRICE_WEIGHTED;
//------------------------------------------------------------------------------
//  SCRIPT start function                                                      |
//------------------------------------------------------------------------------
int start() {
  int CntBars=Bars;
    int Mode,Price,CntBO=0,sumVolat=0,hfile;
    string filename="BarS1.txt";
    double delta=0;
    FileDelete(filename);
    hfile=FileOpen(filename,FILE_READ|FILE_WRITE,"\t");
    if(hfile<0) 
        {
        Print(filename," OPEN Error: ",GetLastError());
        return(0);
        }
    else FileSeek(hfile,SEEK_END,0);
    /*FileWrite(hfile,"Paire","Mode","Price","BarOut[%]",
    "DisM[Pi]","All","VolatM[Pi]");*/
    for (i=0;i<CntBars;i++) {sumVolat+=High[i]-Low[i];}
    //
    for (Mode=0;Mode<4;Mode++) {
        for (Price=0;Price<7;Price++) {
            for (i=0;i<CntBars;i++) {
                indA=iMA(NULL,0,PeriodMM,0,Mode,Price,i);
                if (High[i]<indA) {CntBO++;delta+=(indA-High[i])/Point;}
                if (indA<Low[i]) {CntBO++; delta+= (Low[i]-indA)/Point;}
            }
            FileWrite(hfile,Symbol(),Mode,Price,100*CntBO/CntBars,
            delta/CntBO,delta/CntBars,sumVolat/CntBars);
            CntBO=0;delta=0;
        }
    }
  FileClose(hfile);
    return(0);
}
//------------------------------------------------------------------------------
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