setRowCount with setXml

I've been playing with moving our application to Version 2 of the Grid and I noticed an issue with setXml(xml) that looks like it will make the transition more painful then it should be.

With V2b3, the XML data model requires you to call setRowCount(X) if you load the data via setXML(xml) but setRowCount(X) is not requried if the data is loaded via setUrl(url). This inconsistency doesn't make sense to me. I can see no reason why a forced call to setRowCount(X) would be desired.

I have two questions/requests:

1. Is there a reason why setXML(xml) requires a call to setRowCount(X)?
2. Can the setRowCount(X) requirement for setXML(xml) be removed?

I have the same question. Why do I have to use setRowCount if using a data island, but not if using a url?

setRowCount call is included into table.response() method which is called when the data arrives after url request. With the data island the response() method is not used so you have to call setRowCount() yourself.