A small assembly drawing for a VICD have two -99,-98 items listed on the drawing parts list to identify what is a item 1 and 2 as shown on the Assembly. These "parent part dash numbers" denote and detail what composes the assemblies'sub-components. And, shown separately on subsequent sheet 2 in the same doc.
Others, (mfg) want to treat these dash no.s as complete & separate part numbers by adding the parent part number to the dash number(ie. -99 to 12345-99). and, then re-listing it separately along with the multiple assembly dash numbers. Claiming this would be clearer.
Rendundant,I say if there was to be a lot multiple assembly dash numbers and, a lot of parent dash numbers (-99 thru -88 for instance)on the drawing part list. The P/L would be too large complicated for what otherwise is a straight forward assembly. Especially, if these items are not to be made available separately.
What is the correct standard Ansi or otherwise to follow?

I don't know what the standards say regarding this, but I agree with mfg.  There is a difference between part numbers and drawing numbers.  A complete part number in your example would be the base drawing number followed by the dash number.  We only use dash numbers on tooling, but we still require the complete part number to be called out in the pl, even though the dash numbered parts are detailed in the same drawing.

You really didn't need to start a new thread for this.

"ACCORDING TO: Drafting Requirements Manual for Departments of Defense & Industry by: Jerome Lieblich, Seventh Edition, Chap.10, Pg.10-18, Paragraph:10-7.3.3.3: "Parent Part Numbered Dash Number Entry: When entering dash numbered parts of the parent drawing, the parent drawing number is omitted and only the dash number entered. Parts originaly elsewhere than the parent drawing must have the complete part number entered."
SO...if item 1 is listed as having a (part or identifying No.) of -99. Why would it be again listed again as one of the assemblies multiple dash numbers versions; -1,-2,-3, etc,? Since, -99 is documented within the parent drawing it is thereby not required to be listed along with the multiple dash numbers rows. (-1,-2,-3 etc.)
Sequitur: We are documenting the Assembly(s) and not the individual component/assy items therein,(what makes up the assembly.) Right?"

  Right, according to Drafting Requirements Manual for Departments of Defense & Industry by: Jerome Lieblich, Seventh Edition, Chap.10, Pg.10-18, Paragraph:10-7.3.3.3.

  I admit that practice was followed in the past.  Do you have any current ASME or other specifications which still stipulate that method?  The standards in use today are not as nearly strict as those of 20 years age.  For example, in ANSI Y14.5-1982, you often found that you "shall" do it a certain way.  In ASME Y14.5-1994, you often find that you "should" do it a certain way.  A subtle but distinct difference.
  With the intelligence built into todays CAD systems (and their automated PLs), it is much simpler to use the entire part number.  Not that you couldn't manage to use only dash numbers, but the effort involved would not be worth the trouble IMO.

  I guess I just don't understand how adding the base number makes it too large and complicated, unless you have a long number and many assemblys to deal with, and have to do it manually or with a low-end CAD system.
  I have seen tooling drawings treated differently than other types of drawings, and just using a dash number would be sufficient in most cases.  The problem comes when you are trying to track the individual parts.  If you need to replace one machined part of a tool assembly, its number (base and dash) becomes very important.  You wouldn't send out a PO for "-7", but for "12345-7".  If you make the part in house, then I would think you could do it however you (or accounting) want.
I am curious to know what the current standards have to say about this.