Serial.write and Serial.println return different values? Cannot use correct ones
The text file contains the sequential ascii values that spell out the data, not binary data. println in printing the numerical value of each byte. For example, the 10's println prints are '\n' characters. write is printing the ascii character associated with the binary value (the new line). You need to parse the ascii characters into numbers.

Luckily for you the SD library inherits from the Stream class, so it will have the same parseInt function most often used to parse ints from the serial monitor. 

You probably want to set myFile.setTimeout(0) first because the file isn't slowly getting characters from the serial bus, so the timeout would just slow you down.

Then you should be able to parse and print out the ascii integers with something like this:

int val = myFile.parseInt();
Serial.println(val);