Agree. Drilling was ok with NC headphones but they didn't work for ultrasonic. Too high a frequency which changes rapidly.I believe you'll be fine. The ultrasonic tool (for scaling) makes a loud shrieking sound, but the other tools are less noisy and should not do any damage when used for short periods of time.
I would recommend to avoid the ultrasonic cleaning if offered. It's the only thing that gave me a scary spike in 14 years of tinnitus. Never had any problem with the other dental works though (fillings and wisdom tooth removal).