Precioeuro shows the official exchange rate ± a few centavos, while dolarblue.net shows the exchange rate you can get (or pay) in cuevas in BsAs.
The actual exchange rate in Mendoza last Thursday was 1 Euro = AR$ 9.40 - both U$S and Euro exchange rates are below those in BsAs.
At the same time, the official rate was 1,000 Chilean pesos = 10.8 AR$, but a Chilean friend of mine got 16 AR$.