TCO using wrong child element

We’ve received a number of TC602 (provisional awards) for 2012-13. These include Child Elements based on £2665 (the rounding increases these to £2668.15). The Government initially announced that the Child Element would be around £2665 but later increased it to £2690 (see http://www.hmrc.gov.uk/rates/taxcredits.htm) which would be rounded to £2690.05. But the TCO have been issuing award notices based on the originally announced £2665. We’ve spoken to the TCO but they insist they are correct. I’m wondering how widespread this problem is. To date 100% of the award notices that we have received which contain a child element are using the wrong figure. Anyone else experienced this problem?