Divisional performance

Please cold you help with the following:

Osborne Co is a subsidiary of Butler Co, which operates a decentralised system of management.Group companies have control over their own working capital and make proposals to the main board
for capital expenditure projects. In calculation of Profit, why non-controllable overheads are deducted from revenue. I think not only recharge of head office but also non controllable o/h should not be deducted.

Income statement
(In $000 )
Revenue 8,500
Cost of sales 5,300
Controllable overheads 1,700
Non-controllable overheads 950
Head office recharge 700

Thank you.