Monthly direct material cost of product in process = Monthly equivalent product in process * Flat-rate cost of material per unit of product in process

= 2000*100%*5*4=40,000 (yuan)

Monthly direct labor cost of product in process = Monthly equivalent product in process * Flat rate of wages per unit of product in process

Monthly direct labor cost of product in process = Monthly equivalent product in process * Flat-rate wage per unit of product in process

=2000*80%*2.50*3.20=12800 (yuan)

Manufacturing cost of products in process at the end of the month=approximate equivalent of products in process at the end of the month*unit of manufacturing cost of products in process at the end of the month

=2000*80%*2.50*1.10=4400 (yuan)

Costs of products in process at the end of the month=40,000+12,800+ 4400=57,200 (yuan)

Cost of products completed in the month=Cost of products in progress at the beginning of the month+Production costs incurred in the month- Cost of products in progress at the end of the month

=(28,000+12,000+4,000)+(164,000+60,000+20,000)-57,200

=230,800 (yuan)