Arriving at valuation rate

i need some help on valuation rate
i can enter valuation rate at two places
at the time of stock reconciliation
while creating an item
where should i do it

if there is a typo error and the entry at both above places doesent match then which value is considered ?
for a semi-finished component, what is the valuation rate ?
is it including the raw material and all the process that has been carried out on it?
for example
front cap— finished product
RM front cap - raw material blank - Rs100
cnc front cap - cnc machining - Rs50
Anz front cap - Anodizing - Rs 20

so the total amount to manufacture Front Cap is Rs170
for “cnc front cap” the rate is Rs150
is it how iam suppose to evaluate the valuation rate for the items
Please help