GST liability on works or composite supplies remains governed by...

GST liability on works or composite supplies remains governed by the applicable statute, whereas reimbursement of an incremental GST burden depends on the contract's allocation of tax risk. An inclusive-tax clause must be read with any change-in-law, price-adjustment, tender or award provisions to determine whether the employer owes an adjustment; GST becoming payable alone does not establish reimbursement. Contract-wise reconciliation of pre- and post-GST work may determine a revised GST-inclusive value and support a supplementary agreement where adjustment is contractually justified. Such contractual relief operates only between contractor and employer and cannot permit revised returns contrary to statute or waive statutory limitation, interest or penalties.