Published accounts adjustment

Sir,
I am confused with this adjustment, where the reporting date is 31 march 2017

On 1 October 2016 Pricewell entered into a contract to construct a bridge over a river. The performance obligations will be satisfied over a period of time. The agreed price of the bridge is $50 million and construction was expected to be completed on 30 September 2018. The $14·3 million in the trial balance is:
Materials, labour and overheads $12m
Specialist plant acquired 1 October 2016 $8m
Payment from customer. ($5.7m)
Total construction cost $14.3m
Revenue is to be measured using the sales value of work done compared to the contract price (an output method). The sales value of the work done at 31 March 2017 has been agreed at $22 million and the estimated cost to complete (excluding plant depreciation) is $10 million. The specialist plant will have no residual value at the end of the contract and should be depreciated on a monthly basis.

The solution as follows
Revenue 22,000
Cost of sales.(bal. fig) (13,200)
Profit to date (20,000 × 44%). =8,800

Costs incurred to date 14,000
Profit taken. 8,800
Cash received. (5,700)
Receivable. =17,100

My question is
1. Why the 44% of cost 12,000+8,000=20,000 taken as profit to date?
2.why is cost incurred to date & profit is added together ?