440 Automatic. What gears are you running?

So I asked 3 performance related auto shops here how much they charge to change the gears with me supplying the Motive gears, correct fluid and the install kit. All four shops were between 4 and 4.5 hours labor. I went to a 4th shop that I have used before for difficult stuff that I don't do or if it requires a lift (I'm getting old). They are a very reliable shop. They said they need the car a day and a half (!) and they charge 8 hours labor. I'm thinking that the last shop must be assuming axle bearing change, seals, etc. Do you automatically change out the bearings and seals? What kind of labor do you think for just the gear change assuming the bearings and seals are good?