info about bulletins being replaced by multiple bulletins

[Sean]

I have a basic question that I thought i could easily find an answer to via
google and/or a MS website.

I have recently been diving more into patch managment and I am noticing that
some bulletins are replaced by multiple bulletins. For example, MS08-013 is
replaced by both MS08-014 and MS08-016. My understanding is that each
bulletin replaces a part of MS08-013, not really the whole bulletin MS08-016
does not replace MS08-014. In more general terms, a bulletin replaces a part
of an bulletin and not the whole. Is this correct?

If not does anyone know of site that explains in more details about why a
bulletin is replaced by more than one bulletin?

I know that is a basic question and I have not really had any luck finding
any answers via google or MS and I am somewhat new to PM.

Thanks,
Sean