Here is your problem, from http://blogs.zdnet.com/soho-networking/?p=117
"The difference between the two models is that the WRT310N has Gigabit Ethernet and three internal antennas. The WRT160N lacks Gigabit Ethernet and has only two antennas. Both use MIMO technology but, according to the spec sheet, the WRT310N employs Draft 2.0 of the 802.11n spec, while the WRT160N uses version 1."
DAP-1522 is using 802.11n V2, WRT-160N is using V1 (unless there is - or you have - a FW update to V2)