@econnolly I have the same problem on Linux, using the OpenSuse Tumbleweed OS. The transcoder bitrate does not change from the default, in my case 114kbps.
There are alternatives which do variable bit rate, and support bitrates up to 320kbps, though it would be good to have the choice of better bitrates in Strawberry. I aim to use 160Kbps for playing on my iPod nano.