Overtime hours and different rates of pay

Hi

I am having seriously difficulty trying to calculate the standard, overtime 1 and overtime 2 hours applicable to difference rates of rate on a daily basis.

Standard rates apply 8am-4pm Mon to Thur and 8am-3.30pm Fri

Hours thereafter are charged @ 1.3 the standard rate
Midnight to 8am are charge @1.7 the standard rate
Saturday first 4hrs are charged @ 1.3 the standard rate and thereafter @ 1.7 the standard rate
All Sunday and Holidays are 1.7 the standard rate


A 1/2 per day is standardly deducted for lunch

I have attached what I have currently. any help would be greatly appreciated.