802.11n Speed Issue

I'm using a MacBook Air with 802.11n (verified via About This Mac -> More Info -> Network -> Wifi) which shows Supported PHY Modes:802.11 a/b/g/n. My Access Point is a Cisco 3502 (AIR-SAP3502E-A-K9) support both 2.4 and 5 Ghz.

1 Gigabit Ethernet interface

2 802.11 Radios

My Internet link is approx 100Mbps download (last speed test via wired was 93.5 Mbps download). If I connect via wired Ethernet, I'm getting close to 100Mpbs when running the speedtest via speedtest.comcast.net and selecting San Jose which is the closest point to me. Now if I unplug and connect via WiFi, the mac speed I can ever hit is approx 50 Mbps. Same with another test Mac and IOS devices report the same. What is preventing me from hitting 802.11n speeds? Makes no difference is the Mac is 2 feet of 30 feet from the access point the result is always the same. Everything seems to point back to the access point as the Mac can hit the near 100Mbps when wired. The access point is running Cisco ap3g1-k9w7-xx.152-2.JB. Below are the specs from the Cisco page on the AP and it's speeds. If I am reading this correctly I should be able to hit 300Mbps. Anyone have any thoughts?