Linksys Wireless Router :: E2500 Only Broadcasting At 144N?

I just purchased the E2500 and both bands are only broadcasting transfer rates at 144N instead of the advertised 300N.  My old router broadcast at the 300N rate on the same ISP serving a range of devices.  I contacted chat support and tried to discuss the issue for about 30-60 minutes before getting fed up with the lack of progress on the issue.  The gist I got from the support agent was that I would only be able to achieve the 300N rate in N only mode instead of the mixed mode.  I don't know the available modes of all the client devices that would need to connect but this would not be acceptable as my old router was capable of serving the range of devices while also giving the max rate of 300N to those devices that could utilize it.  I verified the difference in transfer rates using [URL] with my old router giving the higher rates expected from 300N over 144N.