super not calculating

Hi

I have just started using Essentials in January and everything was fine and PAYG tax and super were automatically calculating

However when entering the payrun for the last week of January the super did not calculate automatically on all employees with pays under $450 NOT sure why this is happening

could it be that I have 2 pays for the same dates in January (so have more than 4 weeks) as I had to delete and re enter one employees pay as it was incorrect so have 2 pay runs for w/c 4 January This is the only thing I can think  that may cause this???

All employees make more than $450 per month and I dont want to have to calcultate super manualy every month 

any sugestions

thanks

kp