Contract completed over time

Hello! I have a question from the BPP 2023-2024 kit.
James Co entered into a contract to build an office building for a customer commencing on 1 January 20X5, with an estimated completion date of 31 December 20X6. Control of the asset is passed to the customer as construction takes place and James Co does not have an alternative use for the asset. Satisfaction of performance obligations is measured by reference to work completed to date. In the first year, to 31 December 20X5:

1. Certificates of work completed have been issued, to the value of $750,000.
2. The final contract price is $1,500,000.
3. Amounts invoiced to the customer as at 31 December 20X5 is $625,000.
4. No payments had been received in respect of the receivable at year end.

Required:
What is the amount of revenue recognised in the financial statements of James Co at 31 December 20X5, and what entries would be made for the contract on the statement of financial position at 31 December 20X5?

I do not understand as to why to the total revenue should be 50% of $1,500,000 rather than just taking the value of $750,000 directly, both give same answers but should we not consider the certificates of work completed as having fulfilled the performance obligations for which we recognize revenue? I don’t understand why we take 50% of the contract price?

Also, should we not add the figures for Receivables ($625,000) and Contract Asset (remaining $125,000) to the revenue? Or those are merely used for entry in the statement of financial position?

Kindly let me know sir, thank you!