Multilevel Bill of Material cost sum

Hello, I'm working on tool to estimate Bill of Material Cost. As a input I'll have multilevel Bill of Material with cost assigned to each position and I need to have multivelel summing to be able to verify each level cost(each of postion cost is some of below levels cost). Sometimes I'll have 10 postions and sometimes 200 lines.

Please find attached sample. Thank you in advance for any support.