I did answer your question, and I did so quite precisely. As a
licensed amateur, what part of "2K8J3E" don't you understand?

It's an FCC specification that essentially says "USB carrying
voice of frequencies 300 to 3KHz". Also the FCC specifies
a SSB channel frequency by the frequency in the center of
the transmitted RF spectra. Audio at 300Hz corresponds
to frequency "X-(2700/2)", 3KHz to "X+(2700/2)" where "X"
is the center of the channel. "X" would be 1650Hz higher than
the traditional ham radio method of specifying a USB frequency
(hams specify the frequency of the suppressed carrier). Aside
from 60M, the FCC doesn't specify how we are to specify our
frequencies; they just say "Here's your permitted bands for
SSB, keep all of your RF inside them". 60M is special in
that the FCC wanted hams to blend seamlessly with other existing
users (meaning that those other users could easily listen and talk
(say in emergencies) to us on their existing channelized equipment.
And we got these five specific channels because the other users
don't use them that much compared to other channels.