Tax Free Childcare - Maximum entitlement?

Hi
Just paid my first ever tax free childcare payment following a transfer from Childcare vouchers.

One question i had was that i understood the maximum entitlement per child was £500 per quarter (maybe that isnt correct), i.e £2k PA per child.

Following my first payment i notice that the maximum entitlement left for this "period" is more than the maximum, i.e. £565.

Any ideas how this is?

THanks