Question re V70 oxygen sensor - repair

I've got a 2000 V70 with the non-turbo engine (2.4L). It's been running fine for the past 98,000Km until a few days ago, when it would start up fine, and then immediately die. Onvce running however (after a few tries) it worked AOK. The other day, the check engine light came on, so I took it to my independent Volvo mechanic (in Ottawa). He replaced the oxygen sensor and charged me 3 hours labour for "checking the whole fuel and ignition systems. Given that the computer probably indicated the fault, isn't that a bit much? Any comments? Above all, I don't even see where an ignition problem was suspected.

Thanks,

Rick

 

Which mechanic was it? I had a bad experience with Adria on Bank
Street several years ago, and a good experience with a different
independent on the other side of Dow's Lake. Imagine that, I can't
remember the name of the good one...

 

Three hours does seem a little on the high side for 1 O2 sensor. If they
did only replace 1 then you can probably expect the other to go pretty
soon.