du measures in 4K blocks resulting in inaccuracies

I'm trying to size a disk.  Unfortunately /usr/bin/du is misleading.  An 
example referencing two files, one 60 Bytes, other 908 Bytes:

unset BLOCKSIZE
echo ;         ls -l /projectx/adm/README /projectx/adm/gen_pw.sh
echo "1 ---" ; ls -lh /projectx/adm/README
echo "2 ---" ; du /projectx/adm/README
echo "3 ---" ; du -ckh /projectx/adm/README /projectx/adm/gen_pw.sh

-rw-r-----  1 sysman  wheel   60 Jul 28  2023 /projectx/adm/README  #60B
-rwx------  1 sysman  wheel  968 Jul 28  2023 /projectx/adm/gen_pw.sh
1 ---
-rw-r-----  1 sysman  wheel    60B Jul 28  2023 /projectx/adm/README
2 ---
8       /projectx/adm/README    <<< 8 sectors
3 ---
4.0K    /projectx/adm/README    <<< min count is 4K, so sectorsize?
4.0K    /projectx/adm/gen_pw.sh
8.0K    total			<<< Expect at most 2K

# diskinfo -v /dev/ada2p3
/dev/ada2p3
         512             # sectorsize


Perhaps my understanding is wrong, so to authority "man du"
-k      Display block counts in 1024-byte (1 kiB) blocks.  (incorrect)

-h      "Human-readable" output.  Use unit suffixes: Byte, Kilobyte,
           Megabyte, Gigabyte, Terabyte and Petabyte based on powers of
           1024.    (?  4K)

but even --si gives
4.1k    /projectx/adm/README   # <<< 4.1K??!
4.1k    /projectx/adm/gen_pw.sh

What am I missing?  Should the doc reflect the minimum reporting size is 4K?