I know the difference between the offline xp and the online currency and I never brought that up in my question. My mentioned loss of vc was when I was kicked out of mycareer because of server issues and lost 1000+ actual VC (wouldn't let me upgrade skills for several games but I thought it'd eventually work), which prompted me to make an offline mycareer that wouldn't rely on the servers.
As for the Offline status being the cause, I didn't think a game would limit an upgrade option to online-only careers.