"1 set flywheel bolts (does this mean they pulled out the engine?) $15"
"B. R&I engine assembly"
You answered your own question.

"Compression after work completed was noted as..."
"A. System analysis - compression test 300, 280, 300, 320, 280."

The compression numbers in your first post was *before* the work was done. The low numbers were likely the reason a ring job was done.

$1500 for the work and $400 for outsourced work? Thats a heck of a deal. Many other places would be in the $2000+ range.