Are indexterm ranges backwards incompatible?

After this morning's meeting, I'm starting to think
that maybe ranged indexterm should be considered backwards incompatible
with DITA 1.0.

In 1.0, it is ambiguous whether indexterms point to discussions
confined to a single page, or to extended discussions that begin on a
certain page.

Introducing ranged indexterms removes that ambiguity.

Users who want to make use of ranged indexterms would need to go back
through their entire document set and replace current point indexterms
with ranged indexterms where appropriate - otherwise any new ranged
indexterms they add would cause these old point indexterms to be
misinterpreted.

Doesn't that amount to backwards incompatibility?

--Dana