Before permitting amendment [or supplement], the Proper officer is to satisfy that 

• the IGM is in any way incorrect or incomplete and
• there was no fraudulent intention

The person responsible to file IGM should not be allowed to practice a short-cut route by first filing an incomplete or name-sake IGM purposely to fulfil the requirement of s.30 [before arrival of the vessel / aircraft or within 24 hours in respect of import report] and then come up for a routine amendment to avoid penalty.  

Filing of IGM before arrival of the vessel is most important and sensitive to avoid smuggling because possibilities are plenty to illicitly offload at unauthorized places or remove to.  All the offences mentioned in s.111 could be detected and proved only if it is insisted that the IGM is filed before arrival of the vessel.  As such in each and every case, the person responsible to file IGM should be asked to support the request for amendment by documents in original received from overseas principals for occurrence of mistake or incomplete information. The age-long practice of receiving the manifest by the boarding officers should have already been discontinued due to the changed time of communication facilities.

Amendments resulting in change of importer should be allowed after exhaustive investigation and after obtaining written clearance from investigation agencies viz. DRI, SIIB, DIU etc. In most of the cases of import of prohibited goods viz. toxic and hazardous goods,  or import without valid licence, the actual importers escaped through this route by simply substituting a bogus importer.  

In all such cases, Purchase Order made to the suppliers (in the absence thereof, a letter duly signed by the importer, indicating the name of the person who made oral orders to the person to whom; from and to which telephone No. and the exact and full text of such order should be demanded in all cases.)

With regard to High Seas Sales [HSS] it is usual with most traders to create ante dated documents actually generated well after the goods entered into India, mainly to evade local taxes.  Customs officials should not collude or assist in such evasion by entertaining such belated  request for  amendments.  In almost all genuine cases of HSS, the change of importer could have been notified to the person responsible to file IGM before arrival of the vessel / aircraft etc.

After clearance of goods, amendment of BE or SB or Bill of Export only on the basis of documents existed prior to clearance

Nobody else except the Proper Officer is empowered to authorise amendment u/s 149. So, such officer ought to have been posted to the seat by orders in writing.

Only if the proper officer is satisfied that there was no fraudulent intention, amendments u/s 30 or u/s 41 may permitted.

The following are a few situations where amendment after clearance cannot be requested by the party:-

1. Since discretion of the proper officer is involved in authorizing amendment u/s 149, the proper office may deny amendment in certain situations on reasonable grounds.

2. Revised Invoice is issued after the clearance of goods