How do I make direct expenses add to value of inventory in Tally ERP9?

Have you tried to alter the transaction? 

Have you tried to alter the transaction? 

Could you please elaborate how to do that?

If you drill into the transaction, at the bottom, you will be able to see alter option. I am not sure if that option goes off if the payments are made. Try it and if allows manipulation, then increase the amount+make a note

How to edit/ alter voucher in tally erp 9 ? - YouTube

Thanks for the reply, but I need to make direct expenses increase the value of inventory.

Sorry to hear that. The option you tried to enable is correct. Contact your IT services or else hope that some CA will get ack to you. 

https://help.tallysolutions.com/docs/te9rel66/Job_Work/#gref

This might help including direct wages.