Reported Wireless speed w/ repeater 7-9x Measured Speed

This is my setup:

Cable Modem -> WRT54GS wireless router w/ 100 Mbps wired computer
-> WAP54G WAP in repeater mode -> WMP54GS wireless NIC -> wireless computer

WinXP SP2. Wireless Zero Config is started, no Linksys software
installed for the wireless NIC. The wireless computer is definitely
connected to the WAP54G repeater and not the WRT54GS router (they have
different SSID's).

Network connection properties for the NIC reports the wireless speed is
54 Mbps with 5 bars. But the transfer of a 61MB file from wired computer
to wireless computer takes 60-90 seconds. I calculate a 6-8 Mbps
transfer rate (eg, 61*8/60).

I understand repeaters will halve the connection speed, so I expect
transfer rates in the 20's or thereabouts.

Can someone explain the discrepancy between the 54Mbps reported speed
and the 6-8 Mbps measured speed?

Thanks,

Lance
*****