Same here - my DD's centre charges nearly $10 a day more for toddlers than they do for her agegroup (kindy). The staff ratio in the toddler room is much higher and the number of children much smaller.
This was the case at most of the centres I looked at.
They only provide morning and afternoon tea -we provide lunch and nappies.
At the end of the day childcare centres are a business like any other and they are entitled to charge what they like to cover their expenses and make a profit which is why you see variation between centres.