Sorry for resurrecting this old thread, but I've run into the same problem and I think the OP was misunderstood. In current windows10 console, scrollback is broken for freepascal console programs. Regardless of the buffer size in the console, after the pascal program ends only the visible portion remains in the buffer. If you scroll back you'll see whatever was in the console at program launch.
I'm trying to find a solution for this right now, in case of success I will reply back.