I am going to get flamed but I have always maintained that RIMS is for maintaining mash temperature only. Thats why I always try to brew with fully modified malts. With a fully modified malt a single infusion mash is sufficient so I never to use the RIMS to step. I think we are seeing more and more that using a RIMS to step is going to lead to problems. I think that one has to consider that to step you need to introduce a lot of heat into the mash which demands a slow flow to transfer the heat into the fluid flowing through the RIMS Tube. Thats where the trouble begins. I think if someone wants to step with a RIMS some direct heating of the Mash Tun or decoction has to take place for the step and the RIMS with maintain the rest until it is time to step again.