Scheduled cost is the sum of Total Cost (LCY) in the Job planning lines where line type is either Schedule of Both Schedule and Contract in the planning date filter.
Contract cost is the sum of Total Cost (LCY) in the Job planning lines where line type is either Contract or Both Schedule and Contract in the planning date filter.
Usage Cost is the sum of Total Cost (LCY) in the Job Ledger Entry (calculated in the posting date).
In the Job planning line table lines with types Schedule, Contract and Both Schedule and Contract tables are used for different purposes, so the sum of the costs on each type is also stored in a different fields.
Schedule lines contains expected usage for a job that are not invoiced.
Contract line contains that amount that should be invoiced to the customer(no usage relates to this line).
Both Schedule and Contract lines contains usage that is invoiced to the customer.
Answers
Scheduled Cost : https://msdn.microsoft.com/en-us/library/hh174541(v=nav.90).aspx
Usage Cost : https://msdn.microsoft.com/en-us/library/hh172417(v=nav.90).aspx
Contract Cost : https://msdn.microsoft.com/en-us/library/hh173670(v=nav.90).aspx
Contract cost is the sum of Total Cost (LCY) in the Job planning lines where line type is either Contract or Both Schedule and Contract in the planning date filter.
Usage Cost is the sum of Total Cost (LCY) in the Job Ledger Entry (calculated in the posting date).
In the Job planning line table lines with types Schedule, Contract and Both Schedule and Contract tables are used for different purposes, so the sum of the costs on each type is also stored in a different fields.
Schedule lines contains expected usage for a job that are not invoiced.
Contract line contains that amount that should be invoiced to the customer(no usage relates to this line).
Both Schedule and Contract lines contains usage that is invoiced to the customer.