Furniture - Reuse as ID Credit

I am attempting to apply the principles of this credit as an ID credit for a Leed for Schools 2007 project. Most of the furniture in this renovated school is being reused, with the exception of new furniture for the library addition. Will this apply? Since I have to include all of the furniture and furnishings materials cost to demonstrate compliance with the possible ID credit, do I have then I have to include furniture and furnishings into my calculations for MRc3-7 for LEED for Schools 2007? Or can these be separated because it's being applied to an ID credit?