Non-Salaried Employment in category A and B

[ILR1980]

5.1.3. Non-salaried employment includes that paid at an hourly or other rate (and the number
and/or pattern of hours required to be worked may vary) or paid an amount which varies
according to the work undertaken. Salaried employment includes that paid at a minimum
fixed rate (usually annual) which is usually subject to a contractual minimum number of
hours to be worked.

If a person working with same employer for more than 6 months or year on hourly rate and taking wages monthly which depend on number of hours then he should apply Non Salaried employment under category A or Non salaried employment under category B . Very Confusing as category of non salaried under A is simple while under B ask to satisfy two parts i.e it ask for last 12 months

Can someone clear this confusions?