[C320-list] Maxprop RPM v. boat speed

[Sea Chalet]

I've got a Maxprop on my 2001 C320 with the 3GM30 engine.  I'm wondering 
if I have the pitch set properly to achieve maximum boat speed and 
engine RPM.
This is what I measured (avg. of opposite directions):
2000 rpm - 4.3 kn
2500 rpm - 5.3 kn
3000 rpm - 5.8 kn
3200 rpm (max.) - 6.1 kn.
How does this look?   Should I be getting higher speed with higher max. 
rpm?  Are there any other resources out there to check?
Thanks, all.
Pete Peterson
Sea Chalet
#815