SDCARD write problem

Hey!
So I have this strange case, I created a function to test sdcard and open new .csv file with the current date if the old file was removed or renamed.

In the first line of every new created file I send six words which represent the titles of the six columms of my data. and then, I start sending my data.

dataFile.print("Date,");
dataFile.print("Heure,");
dataFile.print("Machine,");
dataFile.print("Operateur,");
dataFile.print("Produit,");
dataFile.println("Poids");

everything worked well till I decided to add a seventh columm,

dataFile.print("Date,");
dataFile.print("Heure,");
dataFile.print("Machine,");
dataFile.print("Operateur,");
dataFile.print("Produit,");
dataFile.print("Poids,");
dataFile.println("Dechets");

so the progam started sending the seven words everyt time I save new data as you can see in one of the two attached pictures.

but when I keep just six words as in the program bellow , the progam doesnt repeat sending them, even if I send the seventh data as in the picture.

So, anyone have idea about what going on?!

bool newfile=false;
if(!SD.exists(file_today_name)) {
newfile=true;
sprintf(file_today_name, "%02d_%02d_%02d.csv", day(), month(), year()-2000);
}
dataFile = SD.open(file_today_name, FILE_WRITE);
if (newfile){
dataFile.print("Date,");
dataFile.print("Heure,");
dataFile.print("Machine,");
dataFile.print("Operateur,");
dataFile.print("Produit,");
dataFile.println("Poids");
for (int j=25; j<=36 ; j++ ){EEPROM.put(j, file_today_name[j-25]);}
}