Yes, the DMG does state that.
" Recognised Cycles Of Work (Info)
If there is a clear pattern to the claimants work then there is a recognised cycle. The claimant need not have worked a cycle for a recognised cycle to exist.
If a recognised cycle has been established at the date of claim, the hours should be averaged over the period of the cycle to determine if the claimant works at least 16 or 30 hours a week (whichever is appropriate).
Include any periods, within the cycle, in which no work is done, for example rest weeks but exclude any other absences such as holiday or unpaid meal breaks"
I think that given that there are about 13 weeks of school holidays, you would need to work consistently 20 hours per week during term time, so that with your 6 hours during holiday times, you average 16 hours per week. In other words, you need to make sure that your yearly hours total 52x16, so 832.
Examples
-
An employee works a regular fortnightly cycle of 15 hours followed by 20 hours each week. Over the fortnight, this averages 17.5 hours a week. The person is therefore in qualifying remunerative work.
-
An employee works a regular 4 weekly cycle of 20 hours, 20 hours, 20 hours and nil hours. Over the 4 week period, this averages 15 hours a week. The person is therefore not in qualifying remunerative work."
" Yearly Cycle Of Work (Info)
Term time and seasonal workers
Where a recognised yearly cycle of work exists and the person works at a school, educational establishment, or other place of employment on a seasonal basis
- Exclude from the calculation of average hours any periods of school holidays or similar vacations when the person does no work
To calculate the average weekly hours worked by a person who has a yearly cycle
- Divide the number of hours worked or contracted to work by the number of actual weeks worked
Where a person who has a yearly cycle is a new starter or has had a recent change in employment circumstances, follow the guidance in New Jobs.
Where a person who has a yearly cycle is not a new starter, but has not been in that employment for 52 weeks at the date of claim, follow the guidance in this subject as above."
From www.hmrc.gov.uk/manuals/ntcmanual/eligibility_remuneration/ntc0340330.htm