Billing procedure for interstate sales

Dear Sir,

Buyer : Power Generation unit at Kakinada, Andhra Pradesh

Seller: Petroleum corporation, Mumbai

Branch of petroleum corporation : Kondapalli, Andhra Pradesh

Material : Naphtha (Petroleum product)

Issue : Power Generation unit at kakinada, entered in to an agreement for supply of naphtha from mumbai, Petroleum corporation, mumbai will arrange the material from mumbai to kondpalli (their branch) through rail tankers by invoicing on Power Generation Unit, Kondapalli instead of kakinada.Power generation unit has no branch office at kondapalli.

Now the issue is, whether if petroleum corporation raise the bill on the name of power generation unit, kondpalli, power generation unit has to open a branch office at kondapalli or not.

Kondapalli terminal is having the facility of rail tanker unloading, power generation unit have to collect the product from kondpalli and through their transport facilites it has to take the product to kakinada, at which their generation unit is located.

Please advise me the procedure of invoicing, issue of opening a branch account etc.,