AFAIK Cen-Tech is the HF brand for their tools or something like that.
The multimeter PCB is not actually routed. It is cut (stamped?) with a cutter and die. Have a look at the PCB edges and they are kind of frayed, not the clean, smooth edge you get when they are milled.
It costs more to make the cutter but only a one time cost. Then cutting the PCBs is just stamping them out like cookie cutters.
The entire PCB outline is cut including the slots, large and odd shaped holes in just one step.
We did this where I used to work. The prototypes are done as we are all familiar with using milling and drills but once the PCB shape is finalized, the mass produced product will use the cookie cutter thing. I forgot what they call it in the industry.