Two Job rates, two BUs for the same Job code: how the system knows which rate to apply

Summary:

Two Job rates, two BUs for the same Job code: how the system knows which rate to apply

Content (please ensure you mask any confidential information):

We have three Job rate schedules, one schedule per BU(see schedule names attached). Each schedule has the same job codes but different rates because resources have different cost rates per Job for each BU. In the Manage rate schedules there is no where to define or select the BU, so I would like to know how the system knows which Job rate schedule to look at to apply the correct job rate? Please see the attached example.