On February 1, 2013, Arrow Construction Company entered into a three-year construction contract to build a bridge for a price of $8,000,000. During 2013, costs of $2,000,000 were incurred with estimated costs of $4,000,000 yet to be incurred. Billings of $2,500,000 were sent and cash collected was $2,250,000.

In 2014, costs incurred were $2,500,000 with remaining costs estimated to be $3,600,000. 2014 billings were $2,750,000 and $2,475,000 cash was collected. The project was completed in 2015 after additional costs of $3,800,000 were incurred. The companys fiscal year-end is December 31. Arrow uses the completed contract method.

I know the answer is out there, but my question is? should we recognize the loss at the completion of the project or as it occurs

and about gross profit for the last year, I know we must deduct the previous year gross profit but the answer here was deducting the estimated which is 100,000 in this example

please help me