If money isn't directly pumped into the system by receiving banks, then the only direct impact is on those banks balance sheets, which affects their choices and decisions. So the effects to the overall economy are second order, and don't have the same fractional amplification like changing the reserve ratio has.

While I'm an economist, and have training on the model you are mentioning, I'm not speaking from a formal model. Rather from what I've seen in a large bank's treasury while it happened.

Another impact I've not seen considered is what happens when different banks have different effective reserve requirements.