Team MacNN only tracks the RC5-72 side. The interest in OGR has been consistently so low, that we never went there. For example, I've offered several times to extend stats to OGR. Each time, only one person expressed interest. A different person each time, but still only one.
You're probably seeing the low MHz estimate because only ~50% of your power is going to the RC5 side, and because the power estimate is based on a G4. Please be aware that dnetc provides altivec-optimized crunchers by default. The G4s/G5s outcrunch the G3s by far more than MHz would suggest.
It's hard to justify even RC5 today, because it's trying to crack a 72-bit scheme. While everyone has moved to 128-bit encryption.