Paint Matching for Rookies

Q....Is it easier to match paint that's still in the can or on the car?
Match to the CAR, not what you have in the can, there are too many variable that determine the final outcome of the color.
I'm a bit skeptical on those color cameras.
Sometimes they(rarely) get a bang on match, but most times I just used it to get a blendable match, then tinting if necessary.
I tried (my first time) painting single stage on my '69 front clip recently. It didn't go as well as I had hoped.
Since my car was not drivable, I pulled the trunk lid and brought it to the paint shop to get the color I needed, allegedly B5 per their color match camera. Well, it came out too light. So back to the paint shop we go. The color match camera was tried again. It determines there's a hint of green so the Tech re-mixes it.
Yes, I can definitely see that your car is greener than the inner fender, I wouldnt blend the inner color into the car color, it would definitely need to be tinted closer to the cars color first.
Hmmmm..........came out a touch dark this time..........but it is blue, and I still have more BW to do down the sides and I'll need more paint, hence the question.
TIA
What everyone is telling you about blending is spot on(no pun intended), there are too many variables that come into play when spraying that will affect final color, so mix a blendable match as close as you can get to the color that on your car, NOT in a can that you already have, and blend your basecoat into the adjacent panels and then clear the entire blend panels.