802.11b Starts at 2401 not 2400 MHz?

I understand that the "center frequency" of channel one
is 2412 MHz, and that all channels are 22 MHz wide,
so the start (lower frequency edge) of the channel
is at 2401 MHz, not 2400 MHz.

Is this correct?

In other words, is it the case that the "2.4 GHz ISM Band"
starts at 2400 MHz, but strictly speaking, 802.11b does
not start until 2401 MHz?