AC line splice scope of work

I recently replaced my AC compressor which is at the end of about an 80' 1/2" line. The compressor was dead and replacement was authorized. After the new one was installed, the line tested with nitrogen but would not hold pressure at all, indicating a leak somewhere. The leak was located (in the garden) and a new bit of copper pipe spliced in place. The time for the tech to splice in a foot of line was no more than couple hours. The vendor is charging me and arm and a leg and suggesting that a huge new scope work was warranted (more than 8 hours), beyond the splice, because we "had to open up the system and expose it to the environment then restore it all". My expectation was that the splice would have restored the line to the same condition the tech should have expected it to be in given there was no pressure in it when the job started. A line flush would have been required even without a line leak and repair. What am I missing?

source https://hvac-talk.com/vbb/showthread.php?2223945-AC-line-splice-scope-of-work&goto=newpost