@Francisco Jesus Gil Sanandres
The configuration associated with a given deployment never changes as a result of a swap operation: CS01 always has the CS01 config and CS02 always has the CS02 config.
The entire purpose of the operation is to swap the VIP (aka Public IP Address) from one deployment to the other.
I'm not sure what is meant by "each slot maintained its IP". Is this referencing the DIP in classic cloud services? Let me know.
The ip addresses are swapped in Cloud Services Extended Support (CS-ES). As a result, traffic should move to swapped service. If you are using reserved IPs, those values are updated in the cscfgs. However, the configs themselves are not swapped.
Hope that helps. Let me know if you have any further questions.