private residence relief - overseas self employment

I’ve never seen a question that involved the self employed working abroad. All the questions normally involve an employee

here is the question from bpp: Ronald is self-employed. He purchased a house and lived in it for two years. The house was then unoccupied for five years because Ronald went to work outside the UK. He then lived in the house for three years. Ronald then went to live with his mother and the house was unoccupied for six and a half years. Finally, Ronald lived in the house for the last six months of his ownership. How many months of Ronald's 17-year period of ownership of the house will be exempt for the purposes of private residence relief? answer: an excerpt from the answer relating to 5 years overseas is "Deemed occupation - up to 4 years self- employed overseas, plus 1 year any reason" so only 4 years overseas limit for self employed?

Where’s the question come from?