I guess those figures for Stella Blue seem about right, considering hull weight and length, and bottom configuration.
You appear to be more than a little over on wide open RPM (but better to be a little high than a little low).
Our boat has twin Yanmar 370's. We are 42 feet, 40,000 lbs, with a deep v hull.
Our top speed is about 16 knots at 3400 rpm with a clean bottom. If we want to make some time, we generally cruise up on plane, at around 13-14 knots at about 2900-3100 RPM.
Otherwise, we just mosey along at about 1200 rpm and about 8 knots (or even slower), with occasional carbon burning runs.
"It's the tides. They can work for you, and they work against you. And, confidentially, I've had this problem with the tides before." Captain Ron