Boarding sounds on real flights are pretty repetitive, why shouldn't these be?
I must say, I don't know how real boaring sounds sound from the cockpit.
Comparing it to AES for instance, which doesn't sound that repetitive, you have every couple of seconds a person who is greeted with another welcome.
"hello", "welcome aboard, sir", "this way, sir" etc...
Now, I don't like the background noise that starts with the AES, which should actually be present all the time, not only when people are coming in.
I would only suggest that FSDT makes a bit longer file, which would contain couple of different greetings, and that would already solve the repetitive "this way please" which occurs oh every 15 seconds.