3-phase Miller Bobcat: Properly setting DC welds

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I've got a 3-phase Miller Bobcat. As I read the owners manual it says:(Paraphrased)If you set the weld amperage range to "70-150" and you set the fine control to 8, the resulting amperage will be about 110 amps (80% of 70-150).I guess I don't understand. One method to do it would be:If I take 150 minus 70 I get 80. 80% of that 80 amp range is 64 amps. 70 amps plus 64 amps = 134 amps.Another method to do it would be to just take 80% of 150. This results in 120 amps.I can't really think of any other way to figure it out.Let's say I want to run it at 50 amps. Obviously I'll have to set the main amperage selector to "50-100" but what do I do with the fine control. Do I set it at 0? The manual says that ideally you don't want to run the fine control below 7.Any help on this matter would be appreciated. Thanks.
Reply:Thanks. That's what I thought but the math doesn't work out with their example. Like I said, il they say if you select the "70-150" range and then select 8, they say it's set at "about 110". I say (using your method) that it is set at 134.
Reply:Thanks. In truth this machine doesn't see much time as a welder. It has primarily been used as a generator to move center pivot irrigation systems when we don't want to be pumping water. I don't really need it to be perfect, I was just wanting to understand the logic in the owners manual for how they think you should quantify what you have set it. I'm comfortable just setting it so it works so it's not a big deal. Thanks for your thoughts.