HMRC's guidance maps very imprecisely to legislation and case law. Eg the CEST tool asks "Will this work take up the majority of your available working time?"

HMRC's guidance maps very imprecisely to legislation and case law. Eg the CEST tool asks "Will this work take up the majority of your available working time?" Guidance for that question is here: https://www.gov.uk/hmrc-internal-manuals/employment-status-manual/esm11160 https://www.gov.uk/hmrc-internal-manuals/employment-status-m... Can you tell me why they ask it? What light it sheds on the central question of contract-of-service vs contract-for-service?