Petition CSA can't add up! Absent parents are charged double!!

At first glance the rule seem fair. For every overnight stay per week, you pay 1/7th less. However this method of calculation is utterly flawed, it doesn't take a mathematical genius to understand why. As an example we shall say that absent parent pays £70 per week, and for arguments sake has his child (absent parent typically the father) for 4 overnight stays a week. This example would mean you are discounted 4/7th's of the bill = £30, surprising you still have to pay when you are then the main carer! The calculation should be 2/7th's off for every overnight stay, so that should you have shared care your bill reaches zero, which in my opinion is actually fair!! Please sign this petition and recalculate the flaw and repay absent parents!!