This is actually NOT true. The Federal Grad PLUS loan has a maximum of $8,500 per year, regardless of COA. The Federal Stafford Loan that is for grad students has a maximum of $20,500 per year. In other words the maximum amount you can obtain from the federal government (aside from grants) is $29,000 or COA, whichever is lower.
Edit: For Federal Loans the COA that they consider is COA minus any scholarships.
No. What you said is not true. Gradplus covers any additional costs AFTER the initial 20,500 or whatever. If people could only take out as much as you say, there really wouldn't be a debt problem like there is. Unless of course I just misunderstood you. Reread it, nope didn't misunderstand.