you're connected to the flexiroam network when you use it so you...

you're connected to the flexiroam network when you use it so you are using 10mb of flexiroam data- what other cost are you referring to?

if you use your SIP client you need to be connected to the internet? unless you are saying that you would use your SIP clients whilst using flexiroam data?

That would be an interesting experiment actually- switch to flexiroam network, use flexiroam data to call from google voice or something. Might try it if I have some free time later.