Adding Property Set Definitions with a Formula

[Anonymous]

I'm looking to create a cutom schedule that will add up the left and right offsets of hangers to give me a total length of each hanger. Then at the bottom the lengths would be totaled up. 

I would also like to get a total rod length too. I'm new to schedules and property set definitions and i'm struggling with making a formula that will do this. Any ideas? 

[Keith.Brown]

Were you able to figure this out?  If not can you provide a sample drawing of what you have so far?