I have never heard of anyone using the last 300khz.
I don't know if this is the actual reason, but there are frequency allocations in the Asia Pacific region in the 30Mhz frequency range.
When the MUF is high enough I hear Asians all up and down 30Mhz, and some are military in Thailand, and locally for me there are still the odd older style cordless hand held telephones that we don't listen in to. I will have to start a Youtube channel and post some of the video I have of the Asian chatter going on from 30 to 40Mhz even all over 10m for that matter. They even get into the 10m repeaters and create havoc. (watch this space for a future link)