OKC bonding channel question

Internet speed was recently upgraded in my market. I do currently get the advertised speed. The bonding channels on my modem are currently 1 up 3 down, my modem is capable if 4*8. Is that normal? My modem is listed as a Surfboard 6121 and is really a 6141 if that matters. As long as it works  I'm not that concerned, but I know more bonding channels means more consistent service.