[Andreas]

The discount should probably be small. Greater effects come with a very severe cost penalty, so using lesser effects seems to be a better solution for most problems anyway. Also, RPM without greater effects is not without advantages. It can make critical failures much less dangerous (the critical failure of a 20 energy ritual can with greater effects cause enough damage to instantly kill an average person or give you Fanaticism(summon demons) for half an hour without a resistance roll). A -10% limitation on Magery might be reasonable.