The maximum base pay is $160k for the highest roles (all roles in fact). Their revenue per employee is $300k. that's the 0.55. The parent poster is saying that

The maximum base pay is $160k for the highest roles (all roles in fact). Their revenue per employee is $300k. that's the 0.55. The parent poster is saying that in the past the top earning employees had a base pay that exceeded the revenue per employee. Since the revenue per employee number is averaged across all employees, it could still be profitable to employ someone for more than that if the value they provided was higher still