If you look at my earlier charts as compared to the last couple charts, you can see a difference. I started temping orally, as most people do, but found that my chart was really rocky. I was still able to figure out my O date, but it was sometimes difficult. I sleep with my mouth open most of the time and I think that was my issue.
I think my temps are a bit higher now that I'm temping vaginally, but I don't think it's a huge difference. I do like temping vaginally better because I think it is more accurate. Good luck