under what circumstance(s) would be violation?
Basically, you CAN offer certain clients a higher level of service (because they’re paying higher fees) but this ‘higher level’ of service MUST be available to all your clients.
To explain further, you cannot refuse any client that ‘higher level’ of service, as long as they’re willing to pay for it.
Moreover, your act of providing higher levels of service to certain clients must not disadvantage your other clients
Agree with all above, and also the different levels of service must be disclosed to clients and prospective clients.