I think this could either be a somewhat misuse of the word oficioso intending to mean de oficio, or more likely it means diligent etc. The word has a number of meanings

RAE
oficioso, sa.

(Del lat. officiōsus).


1. adj. Hacendoso y solícito en ejecutar lo que está a su cuidado.

2. adj. Que se manifiesta solícito por ser agradable y útil a alguien.

3. adj. Que se entremete en oficio o negocio que no le incumbe.

4. adj. Provechoso, eficaz para determinado fin.

5. adj. En diplomacia, se dice de la benévola mediación de una tercera potencia que practica amistosas diligencias en pro de la armonía entre otras.

6. adj. Por contraposición a oficial, que hace o dice alguien sin formal ejercicio del cargo público que tiene.

7. adj. Se dice de cualquier medio de difusión al que se atribuye cierta representación de órganos de gobierno, partidos políticos, sindicatos u otras entidades.

I think meaning 1 makes most sense here. I do NOT think it means unofficial as this would clearly contradict de oficio.

I suspect it is an unfortunate juxtaposition of similar words, no doubt in the mind of the writer subconsciously.

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Note added at 14 mins (2011-10-15 16:27:56 GMT)
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so the answer is

diligent review



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Note added at 21 mins (2011-10-15 16:35:00 GMT)
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The question is not free from doubt though, and you will have to look to your wider context to make your mind up.

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