This excerpt taken from the PBR 6-K filed May 13, 2009.
REDUCTION IN THE AMOUNT PAID IN FOR CIDE
The calculation of the amount owed as CIDE is made based on the volumes of products sold (gasoline, diesel fuel, etc.) multiplied by aliquots set by the Government that are not dependent on these products sales prices. As such, Petrobras choice for the cash basis for the exchange rate variation taxation had no impact on the amount of CIDE owed. What happened was a change in the way CIDE was paid in, which instead of being in cash was liquidated using the tax credits derived from Corporate Income Tax and CSLL payments made in excess. Therefore, it can be stated that the States should not experience any reduction in their revenues derived from CIDE on account of Petrobras option, since the Unions constitutional obligation to pass the resources on to the States, based on the amounts owed, i.e., regardless of how it will be liquidated, remains.
The lower collection levels of this tax in 2008 is due solely to the fact that a reduction was made in the gasoline (R$0.28/liter to R$0.18 liter) and diesel fuel aliquots (R$0.07/liter to R$0.03/liter) .