I get 25ms unloaded and 27ms loaded with cake running on the latest openwrt rc. If I increase the shaping speed above what the link runs at, that goes up to 30ms loaded.
Incidentally, speaking of the openwrt rc: for anyone upgrading their router with sysupgrade, I usually ssh into my router and run approximately the following to get the system back to being useful and easily configurable after being flashed:
opkg remove dnsmasq
echo "nameserver 1.1.1.1" > /etc/resolv.conf
echo "nameserver 1.0.0.1" >> /etc/resolv.conf
echo "nameserver 9.9.9.9" >> /etc/resolv.conf
opkg update
opkg install luci-ssl
opkg install dnsmasq-full
opkg install luci-app-sqm