You know the meaning of those figures, even though manufactures often print shorter terminology in their public literature. I'v seen the word “accurate” used just as much as “allowable error.” Even though the math terms can be misleading, I doubt that anybody misinterprets ± 3% accurate as being 97% inaccurate when referring to tolerances. I’m not nitpicking. It’s simply understood as “within” ±3% of the “reading.” Say your reading is 15 amps. In that case, 14.55 amps and 15.45 amps are the two possible correct extremes.