Based only on the description, it is not possible to explain in detail what is going on unfortunately. If the receiver models are AMI models, the receiver2's .dll may return the clock ticks in a very different way than receiver1's .dll. Also, receiver2 settings for EQ/DFE could be very different than receiver1 settings. Without looking at the models and the circuit, it is not easy to explain what is the root cause for the offset. If you need more assistance, please open a service request and someone will look for the cause.