Setup Coporate Invoicing (Third party contracts) and interface GL

We have setup corporate invoice (Third Party Contracts), for managing the training / workshop offered  by one of dept. named CEE.

Some of the companies sponsored their employees to take training and for this we need to use third party contract.

We have setup following Account Types :

TPC (Third Party Contract) - Select payment plan account

CTW (Center of Training & Workshop)

Also, we have setup following item types for testing purpose:

200000001000 Fee (Account Type = CTW & TPC)

I.e we are using same item type to apply charges on student and corporate

200000000001 Deferred to Third Party (Account Type= TPC)

We have then applied the charge on student using the