Month 1, year one. How to calculate:

Monthly bonus dividend = [ 1 months / 120 months ] x ASB bonus declared for that year % x lowest minimum balance of that month

Repeat this calculation for each month of the year, from January to December.

Why 120 months? Essentially, the bonus will only realize itself for the money that has been in the fund for more than 10 years! Because that money you put in 10 years ago would be getting 1/120 of bonus for that month for that year for the next 10 years, 1/120  x 120 = 1, hence you would realize the bonus is 120 months!

Dammit this is the most difficult concept to explain. I can explain pretty much anything, but ASB is a weird-ass fund.