Generally speaking, throwing changeups to same handed hitters is usually discouraged. Hoffman didn't have a reverse split for his career. Johan did, but by very little. Also in general, splits are often influenced by selection bias...a good LH pitcher, for example, will face mostly good or better LH hitters and few average or worse LH hitters. The LH hitters left in the lineup to face him are the ones who aren't platooned for. I believe my point stands...I'm skeptical of most any reverse platoon split. They're rare, and even then I'm skeptical it really represents what it seems to represent.