A decent shop ought to be able to provide very accurate cut, the machines are very precise, trick is adjusting files for kerf width of the laser. A good shop will know what the required off-set would be to make cut file match spec'd dimensions. When I was doing this with acrylic I think I had to off-set .02" to make cut accurate dim. I am assuming the Rossman was made on a router/spindle CNC. The "drill holes" in the corner are how you would set-up the file to allow the machine to create right angle corners without leaving curved inner corner resulting from the dimension of the bit you are cutting with. The CNC router/spindle is accurate at least to the thousandth of an inch and will happily cut aluminum. I have less experience with waterjets, we did order a few pieces but there accuracy was not important.