Should people grade their own JLPT tests? We don't actually even have to make an analogy, I will keep it straight. By claiming that you have proofread your work, you are claiming that you found your translation to be without mistakes. Obviously a translator should think so, that shouldn't need to be said at all. If a translator were to find an error in their translation, then they would correct it, no? Then what does it mean to be a doublet TL/PR? Yet the usefulness of a potential proofreader is ever obvious. Pg. 37, our protagonist asked for something in the top panel. But in the next, it is instead the guildmaster who asked for it. Clearly there is something amiss, and it isn't even a matter of bad Japanese or English but of bad conception of basic human dialogue or interaction. One would have to be impossibly dull to misread the scene, but rarer things have happened. What's the likelyhood of a proofreader also being as dull as the TL here? Even if it happens to everyone (it does, and no amount of "novels" can make you immune), one would think that the odds can be played by doubling up on review, that even if a proofreader can be as dull, it's unlikely to occur on the same page, on the same back-to-back panels, for which it occured for the TL. This is obvious to anyone who works, neverminding translation particularly. In your application of the concept, proofreading is devoid of meaning. Its adoption in the credits is an empty emulation of others, probably stemming from arrogance, hence saith thou "I have been trained by the CIA in gorilla Japanese for 6 years and have over 360 confirmed novels..."