Local mechanics disagree on hours to replace control arms

What is your question?

I have one mechanic telling me their system (uses Mitchell) says it takes approx 10 hours to replace the front lower control arms (with ball joints). I have another mechanic (uses All Data) says it takes 2-3 hours per side. Side note: I've gotta do the upper control arms, lower control arms, and rear control arms, all on both sides, so if you've got any info on reasonable rates for any of that, please feel free to elaborate. The guy I bought this from really messed up the suspension...