Lawrence - 4 is a little low but it was down from 6 as a result of fatigue and 6 is OK. During FGB at the certification seminar this weekend I pulled for a 21 for each of the 3 rounds. I started on the rower so I had the full minute. By contrast I'm good for a Tabata row score of 8. Your FGB 4 row score will be less than 3x your Tabata score.
I doubt your rower is broken, but I'd take a look at the damper setting. If you have it up at 10 your pulls will feel like your pulling a barn door with oar locks towing the barn. Drop it down to 4 and you will get a faster pull.
When you pull from the hole take two or three short pulls to get the fan going and then extend to your full pull strokes. Look in the upper right hand corner of your data screen and keep your SPM (strokes per minute) somewhere in the neighborhood of 30...anyway, that's what I do. Play with that number and find what yields you the best distance per stroke and fastest time per 500. Just like with the Olympic lifts your arms are simply ropes that attach your legs to the pull handle. Start with the legs and no arm bend and as you get to max leg extension start leaning backwards and pull to between belly button and nipple line. Breathe out as you pull and take a short rest and breathe in as you pull back to the starting position.
Keep rowing, incredible metabolic challenge. Start keeping score so you can see how you improve over time.