I hate that you can't post to the groups with easynews. I also have NO need for a web interface, their retention is better than some but still sucks, and for the money... For another buck you could have WAY more retention, be able to post for requests, and never have to worry about what you've used. Not that you seem to be going overkill at the moment with bandwidth.
My advice.. Pick something else..
One plus about easynews.. if you use NNTP (not the web interface but a client) you are only docked for 75% of the bandwidth , and they don't count against your limit.. But then again retention is lower on the NNTP servers because more groups are available..
To compenstate for UUE overhead, EasyNews only counts 75% of data transferred from NNTP.