SE550 at 6400' elevation

Noob question..

i took my SE out over the 4th of July weekend. I had it out at Gold Lake (Plumas County, NorCal) and Donner Lake. Put a few more hours on it while waiting for appointment to get all the issues addressed.

I was pretty stoked about one thing. I've never surfed. Nobody on the boat had surfed, yet I got up on the third try! Can't wait to spend some more time on it.

With 6 people in the boat and full ballast, should the boat be able to get on plane? I tried it in wake board mode (cruise on) and with the cruise off. Wide open throttle at either setting would net 3800-4100 rpm, nice view of the sky and like 16-18mph. Seemed to run fine when empty.

Just curious. If that's normal then thank goodness I have the 550 not the 450. About 1/2 the time I'm in the Sierras.