Maintenance Contract spanning over 1st April 2015

If my company has a software system support services contract with the customer from 1st Oct 2014 to 30th Sep 2015 value at RM12K for the 1 year period (payment fully received), do I have to CN RM6K on 31st Mar 2015 for the remaining contract value from 1st Apr 2015 to 30th Sep 2015, and re-issue Tax Invoice for RM6K with deemed inclusive tax of 6% on 1st Apr 2015?

And for the re-issuance of Tax Invoice for RM6K, if my company is going to absorb the GST, can I issue the Tax Invoice with the Contract Value of RM5,660.40 plus RM339.60 GST (6% of RM5,660.40)?

Thanks in advance for any reply and attention to my issue.

If you are going to deem GST-inclusive, there is no need for you to issue tax invoice, just account for the GST output tax in your first taxable period:

Dr Support Services Clearing A/c RM6,000.00
Cr Support Services Clearing A/c RM5,660.38 (Tax Code: SR)
Cr GST Output Tax RM339.62 (Tax Code: SR)

If your customer is GST-registered and they can claim the GST on this support services, then charge them the GST amount of RM360 (RM6,000 x 6%). Do the credit note @ 31/03/15 and tax invoice @ 01/04/15.

Sorry, the correct accounting entries should be:

Dr [BS] Support Services Clearing A/c RM5,660.38
Dr [PL] GST Expenses RM339.62
Cr [BS] Support Services Clearing A/c RM5,660.38 (Tax Code: SR)
Cr [BS] GST Output Tax RM339.62 (Tax Code: SR)