If I read the chart correctly, if Steve were to move onto his optimistic line right now he would end up around 6,000 miles ahead of the record.
Clearly he isn't going to up to those kind of mileages immediately, but it does give an idea of the buffer that he has to use up. On another thread, I said Steve won't beat Tommy's mark in 2015. Looking at jo's projections, it actually looks achievable.