FRRevenue: Recognition of profit

I am struggling with recognition of profit for performance/obligation recognized overtime: BPP revision kit 2021: Bridgenorth Co case: B. Co has undertaken a $5 million contract to repair tunnel, contract sign on 1 January x8 and expect to take 3 years. contract measured according % of work completed as certified by the surveyor. The customer gains control of the asset as each stage of the tunnel is completed. B CO. has enforceable right to payment for performance complete to date. Total contract value: 5000 Costs to date: 2300 Estimated cost to completion: 2100 Work invoiced to date: 2000 cash received to date: 1500 % certified complete: 50 % Question: what profit recognized Now there is nearly exactly the same quesiton in BPB revision kit 2020 (just change the % certified complete to 40%). But there were 2 answers: in BPP 2021: Answer is revenue = 50% x 5000 = 2,500 Expenses = -2300 Profit = 200, While answer in BPP 2020 is: (the actual percentage in BPP 2020 is 40%, I took 50% for easy comparison) revenue= 50%*5000= 2,500 Expenses= 50%* (2300+2100)= 2,200 Profit = 300 Can you help to advise which way is correct? Thank you very much