On my main device, the "Data" size doesn't match. But "Code" and "Cache do match.
On the SM-J327VPP (Galaxy J3 Mission, Android 8.1), all sizes match (because of the bug)
I haven't described the whole bug. I'll clarify now:
The J3 Mission shows incorrect "Data" and "Total" sizes, because "Data" is actually "data_without_cache + cache" (I noticed this, because everytime I clear-cache any app, the "Data" decreases the same amount that was cleared). The "Total" is calculated like so `code + data + cache` (but since `data = data_without_cache + cache`, then `total = code + data_without_cache + 2*cache`)
IIRC, the J2 Prime also has the same issue as the J3M