2nd beta is in... mixed feelings

jmb7712

So my level on Friday am was 244 (14dpiui) and today (17dpiui) was 485. The nurse said it was fine and scheduled me for my first ultrasound on the 22nd and said I didn't need my levels checked anymore because it "doubled which is what we wanted to see." I was hoping for a little higher of a number. Should I be concerned at all because its not any higher? Thoughts anyone?