'Submission of C form mandatory for availing lower sales tax'

Please clarify applicability of VAT or 'C' form for the following transaction. We are located in Chennai and have received an order from Doosan Power Systems Chennai office for supply of supports to NTPC Kudgi in Karnataka. Dooasan is an EPC contractor to NTPC. We despatch to Kudgi site under instruction from Doosan. The order says two per cent CST and not VAT. Tamil Nadu commercial tax department says that 'C' form is not applicable and it should be VAT. This issue is under dispute. What is the solution for this case?
As per Section 3(a) of Central Sales Tax Act, 1956, 'Inter-State Sale' takes place if the sale occasions movement of goods from one state to another. Location of the buyer and seller is immaterial. Thus, even if buyer and seller are within the same state, the sale will be 'Inter-State' if the sale occasions movement of goods from one state to another. Inter-state sale is also possible by transfer of documents even when buyer and seller are in the same state. You may refer to judgments in the cases of Cement Marketing Co. Vs State of Mysore AIR 1963 SC 548 = 3 SCR 792= 14 TC 175 (SC) and KC Metal Industries Vs CST (2010) taxmann.com 115 = 3 GST 429 = 35 VST 403 (Bom HC DB). Form C is declaration by purchasing registered dealer to obtain concessional rate. Submission of C form is mandatory for availing lower CST rate. It is not an alternative to VAT.

Is the validity of advance authorisation for physical exports the same as export obligation (EO) period?
The advance authorisation for physical exports is valid for 12 months for the purpose of imports. The normal EO period is 18 months. In case of turnkey projects abroad, the EO period shall be co-terminus with the contracted duration of the project or 18 months, whichever is more. EO for items falling in categories of defence, military store, aerospace and nuclear energy is 24 months or contracted duration of the project, whichever is more. EO period where specified inputs falling under Appendix-4J of the Handbook of Procedures, Vol. 1 shall be as mentioned in the relevant column of the said Appendix.

We had imported a consignment of chemicals. We drew samples, tested the same and found the consignment unsuitable for our use. We have re-exported the consignment to the seller and claimed drawback under Section 74 of the Customs Act, 1962. Customs say that since we have drawn samples and tested, the consignment has been taken into use. So, they want to pay drawback at reduced rate. Are the Customs correct and can we contest their decision?
I think the Customs are wrong. You have only taken into use a few milligrams for testing. That does not mean that the entire consignment has been taken into use. I think you can certainly contest their decision but I do not find any useful case laws to help you fight your case.