Pic rel is the Chinese domestic armor standard. It's separated into six levels, with Level 6 being equivalent to 7.62x54R LPS and thus significantly below NIJ Level IV.
There exists a "Special Type" above that rated for an equivalent to 7.62x54R B-32 API, which is comparable to SOCOM sandbox plates like the LTC 28595 and still well below NIJ Level IV.
If we're evaluating the XM7's ability to pierce Chinese plates off of outperforming B-32 API, then the math is much easier than trying to pierce Leve IV. Still a huge walkback from what the program was targeting years ago.