Although the Credits state that MEP and other products should be excluded, may they be included in the calculations if desired?

I have the opportunity to get recycled content in piping and manhole covers (Div 22 and Div 33).

Can I use these in my calcs?

If so, do I have to include the total costs for this divisions? everything in plumbing or site utilities?

Example - If I were including furniture from Div 12 would I also have to include window shades from Div 12?

The same total material value must be used throughout the LEED credit calculations, so if MEP products are included, how must everything else in the Div be included in Credit calculations?

Thanks