That's right, C699T GG is the version which has a risk of higher homocysteine. But there are three different ways in which homocysteine is disposed of: via CBS, via BHMT, and via MTR/MTRR. So even if your CBS is a little slow, the others (which are the more useful ones as well) might be functioning well enough to handle any excesses. As far as getting things "working" and ending up with high homocysteine, it depends on what you're trying to do. If you want to slow down CBS, etc, then higher homocysteine might result.