man page has misleading info about the min bw rate
GENERAL OPTIONS BandwidthRate N bytes|KBytes|MBytes|GBytes|KBits|MBits|GBits A token bucket limits the average incoming bandwidth usage on this node to the specified number of bytes per second, and the average outgoing bandwidth usage to that same value. If you want to run a relay in the public network, this needs to be at the very least 30 KBytes (that is, 30720 bytes). (Default: 1 GByte)
The number has been lifted to 250KBytes in our online documentation and this one should probably get fixed too. Anything below 250KBytes (each direction) is probably hurting the network.