I have a rate limit set by radius:
1024K/512K 1200K/1200K 1200K/1200K 10/10

According to the MT documents:
rx-rate[/tx-rate] [rx-burst-rate[/tx-burst-rate] [rx-burst-threshold[/tx-burst-threshold] [rx-burst-time[/tx-burst-time] [priority] [rx-rate-min[/tx-rate-min]]]]

After radius creates the queue on the Mikrotik, it is showing:

Target Upload: 1024k
Target Download: 512k

Isn't this backwards? Download should be 1024k and Upload should be 512k.

Im assuming that rx means download and tx means upload according to the Mikrotik documentation.

Best think of it from the routers perspective - RX is what the router is receiving, TX is what it's sending. Same applies to accounting.

Thinking things from the client's perspective is a quick way to get very confused.

I should have read the documentation a little closer... like you said:

from the point of view of the router (so "rx" is client upload, and "tx" is client download).

Thank you