Between January and December 2006 the waste collection service increased by $ 1,647,340 in the neighborhoods of Palermo, Belgrano and Núñez, the area where AESA operates. According to a report by the General Audit Office of the City of Buenos Aires (AGCBA, for its acronym in Spanish), the increase, which is 40.2%, revealed "errors in the preparation of the Bidding Documents and Conditions" By the Government of the City of Buenos Aires. Among these shortcomings, the control body noted that the files "do not establish a ceiling that determines the maximum cost to be paid by the urban sanitation service awarded."

At the beginning of 2006, that service cost $ 4,097,375 per month. The figure came from a decree from the previous year and remained at that level until June. As of the second half of the year, the City Administration established by decree 720 a mechanism to provisionally adjust the concession contract and the quota increased to $ 4,473,104. Then, with decree 1539, it extended the "service delivery indexes", that is, it modified the limits of some equations that measure the efficiency of the work of the company, thus, the cost happened to $ 5,480,387. And finally, it approved with decree 2072 another variation that took the price to $ 5,744,715 in December.

The value to be paid for the contracting is fixed and unchanged and does not admit the recognition of higher costs, unless a company proves that its rendering became unfeasible. You can only increase the price paid by the State when there is, at the same time, an increase of the service of the contractor, for example if it sweeps more blocks. This increase should not exceed 10% of the total value of the tender. Decree 720 signed by the Buenos Aires Government in June 2006 "touched the limit allowed by the specifications," says the AGCBA, and decrees 1539 and 2072 exceeded the allowable increases in the file for all of 2006.

Another of the shortcomings detected by the Audit in the bidding documents is the lack of details on how environmental studies should be done by contractors. Before starting their work, these companies have the obligation to present a "work base", which is the measurement of the contamination recorded by water, air and soil in the area that corresponds to them. With these parameters a "zero state" is established, which, in order to measure the environmental impact of the service, must be compared with the examinations that must be carried out by the providers every six months. The case of groundwater is a sample of the shortcomings of the tender: these surveys of the companies must include the monitoring of at least three wells, but the file does not specify the areas that have to be analyzed. This, according to the AGCBA, leads the provider to choose groundwater wells, knowing that the water table is contaminated and offers a "dubious frame of reference" that measures the actual impact of the waste collection service.