Normal converstational speech is 55db HL. A moderate hearing loss, when adequately amplified will often score in the 90-95% range of monosyllabic speech and 100% sentence. Ive seen a few with CI who score 100% sentence. Ive also seen a few with severe loss score 100% as well. I know a guy with 80db HL(flat audiogram) who scored 100%, he hears better than most of his deaf friends with CI. Everyone is different, some do well, some don't. What im looking is for average. Some are above average, some are below average.
http://www.alldeaf.com/hearing-aids-cochlear-implants/69092-degrees-hearing-loss-speech-scores-3.html See this thread for figures.
It's rare to score 100% even on a sentence test with CI, but ive seen a few who got that. On a harder test, such as monosyllabic word, they may score around 70% which is considered exceptional for a CI, but average for a 70db HL.