Exactly. But STD is short for standard, meaning that cable channels 14 - 22 fill in the large space above the FM band between channels 6 and 7, then just march up the band above channel 13.

As for HRC and IRC, the practical result of having your switch set wrong MAY be that SOME stations do not come in in color. Otherwise you might not notice it.

And now, a quote:

""HRC" is harmonically related carriers. "IRC" is incrementally related carriers. These are schemes that some cable systems use to reduce the visibility of beat products.
"By harmonically relating the carrier frequencies themselves it is ... possible to improve system performance. This does not reduce the beats produced, but positions them within the system transmission spectrum such that they are more tolerable. In effect, all signal carriers are spaced precisely 6 MHz apart, thus all beats generated are at 6 MHz increments.
"Since the television signals are vestigial sideband modulated, if the beat products can be manipulated to fall on or near the RF carriers themselves, they are much less offensive.."

--from William Grant, Cable Television, 2nd edition, GWG Associates, Schoharie, NY, 1988, page 82