My son ( a "Jr" ) just made elite for the first time. He was having problems upgrading on NW flights with EUA. Here's what I was told by Ms. Mamood in Onepass:
They have just discovered a "glitch" in NW's system. If you happen to have any suffix on your name, the NW EUA will not read your PNR. The only way around it is for OnePass to eliminate the space between the last name and the suffix. So now, my sons last name reads BENSONJR. Ms. Mamood also said that any time we have a problem with EUA, we should call Onepass with our PNR, and ask the agent to fill out a "system issue form" so they will have an example of the problem, and look into it.