I don't understand the last part of the solution how did they got the numbers ( I draw a box around it)

Sandstorm is a jobbing engineering concern which has three production departments (forming, machines and assembly) and two service departments (maintenance and general). The following analysis of overhead costs has been made for the year just ended Rent and rates 8,000 Power 750 Light, heat 5,000 Repairs, maintenance: Forming 800 Machines 1,800 Assembly 300 Maintenance 200 General 100 3,200 Departmental expenses: Forming 1,500 Machines 2,300 Assembly 1,100 Maintenance 900 General 1,500 7,300Depreciation: Plant 10,000 Fixtures and fittings 250 Insurance: Plant 2,000 Buildings 500 Indirect labour: Forming 3,000 Machines 5,000 Assembly 1,500 Maintenance 4,000 General 2,000 15,500 52,500 Other available data are as follows.Effective Direct Labour Machine Floor Plant Fixtures horse- cost for hours hours area value & fittings power year worked worked sq. ft S Forming 2,000 25,000 1,000 40 20,500 14,400 12,000 Machines 4,000 60,000 500 90 30,300 20,500 21,600 Assembly 3,000 7,500 2,000 15 24,200 20,200 2,000 Maintenance 500 7,500 1,000 5 General 500 500 - 10,000 100,000 5,000 150 75,000 55,100 35,600 Service department costs are apportioned as follows. Maintenance General % Forming % 20 20 Machines 50 60 Assembly 20 10 General 10 - Maintenance 10 100 100Required Using the data provided prepare an analysis showing the distribution of overhead costs to departments. Reapportion service cost centre costs using the reciprocal method.Solution Analysis of distribution of actual overhead costs Basis Forming Machines Assembly Maint. General Total S Directly allocated overheads: S S S Repairs, maintenance 800 1,800 300 200 100 3,200 Departmental expenses 1,500 2,300 1,100 900 1,500 Indirect labour 7,300 3,000 5,000 1,500 4,000 Apportionment of other 2,000 15,500 overheads: Rent, rates 1,600 3,200 2,400 400 400 Power 8,000 2 200 450 75 25 0 Light, heat 750 1 1,000 2,000 1,500 250 250 Depreciation of plant 5,000 2,500 6,000 750 750 Depreciation of F & F 4 0 10,000 50 25 100 50 25 Insurance of plant 250 3 500 1,200 150 150 0 Insurance of buildings 1 2,000 100 200 150 25 25 500 11,250 22,175 8,025 6,750 4,300 52,500Basis of apportionment: 1) floor area 3) plant value 2) effective horsepower 4) fixtures and fittings value Apportionment of service department overheads to production departments, using the reciprocal method Forming Machines Assembly Maintenance General Total $ $ $ $ Overheads 11,250 22,175 8,025 6,750 4.300 52,500 1,350 3,375 1,350 (6,750) 675 4,975 995 2,985 498 497 (4,975) 99 249 99 (497) 50 10 30 5 5 (50) I 3 1 (5) 0 13,705 28,817 -9,978 52,500