The focus point is an interesting region of the cMSSM parameter space at high $m_0$ and low $m_{1/2}$. Features are high scalar masses (> 1-2 TeV), light charginos / neutralinos (which are higgsino-like), and fairly low fine-tuning. One can also achieve correct dark matter relic densities and the correct higgs mass.
There seems to be a curve in the $m_0, m_{1/2}$ plane in this region, where if you approach it, the $\tilde\chi^0_2 \,\tilde\chi^\pm_1$ cross section goes up radically (maybe even diverges, spectrum generators can be finicky in that region). Why is that so? You can also rephrase the question, why do the chargino and neutralino masses go down there? I'd expect to first order a simple relationship between $m(\chi)$ and $m_{1/2}$, but around the focus point the masses seem very sensitive to $m_0$.
I guess this is due to the renormalization flow of the particle masses. The slope of the running masses seems a bit steeper than usual in focus point SUSY. There seem to be some interesting cancellations going on. It would be great if someone could elaborate on this.