I wasn't prepared for this question at all; I hadn't at that point in previous roles needed to know that information, and I hadn't understood the business / technical balance of the role. In short I was cuaght out. The problem with the EPP poll command unlike almost all the other EPP commnands is that it isn't stateless; this can cause problems with developing your EPP code for both the server and client by having to handle both stateless and stateful behaviour in the one code base. This can then lead to problems, for example with customers; they manipulate an object (say for example a glue record), and you may get an initial 1000 return code, you then respond to the customers web form (HTTP POST) with success. Then you get the asynchronous service message via poll from the registry informing of an error. Most customers won't revisit the site after making changes and so wouldn't get notification of the error, this then means you need to email the customer of the issue. In effect the statefulness of poll and service messages means writing more code, and more complex code.