Hi Tim
I think you might have misunderstood,
the issue is
"whether even Invoice should have PayableAmount as mandatory"
In other words, should PayableAmount in LegalTotal (or whatever
the document level totals in Invoice get called) be mandatory? I
say absolutely not. Your idea for the Order, etc of an anticipated
total which is not necessarily the actual payable total is also more
like what an invoice needs except that there are legally binding
aspects of invoice totals which are not quite like what you have
decided for orders, etc.
1. should invoices have a catch all mandatory amount?
- i appreciate the desire to have a mandatory amount but which
of the amounts that should be would differ from invoice to invoice
2. should the payable amount be mandatory?
- this is the one amount which is particularly not always possible to
state in some invoices
3. should there be something like payable amount which is mandatory
but has different semantics?
- i think this is just confusing things
4. should there be a payable amount which is optional?
- i think so
The need is to have a payable amount for some instances of invoice or,
in line with 3 (so here i'd advise caution that there could be confusion)
there could be an anticipated payable amount but even that would be
inappropriate for some invoice instances so it shouldn't be mandatory
either. In short, the nature of invoice, it seems to me, is such that the
specific total which is appropriate differs from instance to instance subject
to strict but complex and divers rules. Trying to embody such rules into
to schema, other than in a relaxed way, is likely, i think, to result in
an over-engineered and often unusable (without problematic workarounds)
base standard. Hence I advise not making either amount mandatory.
All the best
Steve
>>> Tim McGrath