In the industry it's fairly well known (ok that's a weasel phrase even though I'm sure I'd be right if I used 99.999999%) in regard to the overall benefits of TAs (Trade Assistants.) Typically a TA around welders, they're grinding and readying the surfaces to be welded and helping position the work. Though there's value in setting up, not just making blue light, welders generally receive a much higher pay packet, since ultimately it's their good welding skills that ensures quality welds leave the floor and a long life of the component.
What's obvious is what would have happened if the blue light was 50 or 60% of the time and the welding machines were at capacity. (Higher capacity welding machines are generally a lot more expensive.) To the clueless a lot more can be squeezed out ... and that's what the hero would have aimed to do, in fact no doubt another 25%. The experienced plant manager would have then kindly thanked them at that point perhaps realising the consultant was out of their depth.