It probably depends on the timing and the nature of the additional work.

For changes made *inside* the LEED Boundary after the Design Phase review, but before the Construction Phase review, you would normally have to revise your submissions to include the changes to the work. The design phase review gives preliminary approval of credits based on the assumption that the work will be constructed according to the plans submitted.

If the Construction phase submittals are already in, it's water under the bridge.

Whether the additional work outside the LEED boundary should be added to the LEED Boundary: I don't think 2.2 offers precise guidance on this, but you could reference pg 19 of the 2009 Supplemental Guidance for Minimum Program Requirements and see if that applies to your situation. If those conditions apply, it would seem reasonable to exclude the additional work.

If the additional work directly supports the building and impacts credit requirements, it could be difficult to exclude, even if done under a separate contract. For example, if the work was an additional parking lot used by the LEED building, that could change your parking counts, open space %, and pervious areas and thus affect SSc4.4, 5, 6, and 7.1.

Hope that helps.