Not neccessarily, if he bought a new van for £20k and new equipment for £20K, then Annual Investment Allowance may well turn his accounts profit into a loss.

So if for instance he draws dividends of £28,000, salary of £9,000 and receives interest of say £7,000 - HMRC software will calculate his 2017-18 liability to income tax at £1,737.50, whereas the correct liability is £125 less at £1,612.50 .