I have ordered a lot of metal from there, its all saw cut, by no means machined ends, that would be pretty stupid, 90% of the time its dead on or as close as you can measure with a tape measure.
Are you gonna use every bit of metal you purchase from there?
If you mean by having the custom cut peices, in your order, specify that you need it cut quite acurately and it will be cut, wrote "cut the 2x2 peice as acurate as possible" and I ended up with like 3 of them all extremely close. theres only so much acuracy you can get out of a bandsaw or a sheer.
This is why I mill all of my ends
Jon