I'd argue that if that's consistently happening, you're overbooked. If you book more people than you can reasonably expect to serve on time, that's being overbooked.
I see that as no different as the shitty companies that have an IBR that repeatedly tells you about 'higher than normal call volume' no matter when you call and anytime you call for months/years. At some point you know your normal and aren't staffing or booking at proper levels.