Changing the line-height

Today's issue on line-height (see
http://tools.oasis-open.org/issues/browse/OFFICE-3847) was written on
the problematic of change-tracking.
What change-operation for XML should exist for line-height? Although we
have currently 4 ODF attributes, from my current observation all
implementations are using them exclusively, so it could be one attribute.

Is my observation correct?

Best regards,
Svante