Revisited: do add-on domains work like regular domains?

Trying to understand the roles of name servers and host

[albo]

(I couldn't append to [webmasterworld.com...]
so ...)

I'll phrase my understanding in simpleton terms: is this analogy correct?

The Registrar knows the name of the Main domain and addresses traffic thereto to "point a" on the Host. (Yes, dns records, of various and sundry sorts...)

The Registrar knows the name of the Add-on domain and address traffic thereto to "point a" on the host.

*Because* of its status, Add-on has its traffic redirected gracefully by the intelligence of the Host server. And at the Registrar control panel end, both domains are set up identically.

Is this correct?

(And, though I understand add-on.com may not have a subdomain, it is to be hoped, I may have a CNAME describing www.add-on.com)

[Webwork]

I'd say yes but there's always a) the uncertainty of words and meaning, particularly as applied to technology; and, b) my gut impulse that the best person to answer such questions if always the customer support person at the service provider because presumably that person knows all the details of the technology (hardware/software) that applies.

Argh. Wish I had a better answer but, seeing the absence of replies, I suspect everyone else looking at this thread had similar difficulty fashioning a reply.

Or maybe, in silence, all the folks smarter than I were simply saying "Yes"? ;)