I have a similar method, works best in winter. I have a IC which has garden hose fittings soldered on both ends. At flame out I hook up the sump pump so that it is in a large bucket ( or my MLT cooler) filled with ice and snow and water. The pump cycles the ice water through the wort then back to the bucket of ice. As the water rises in temp I drain some and add more ice&snow. When I hit 120F I drain the wort through a coil submerged in ice water.
All in all the system is overly complicated, because it was scavenged for free. Ideally I want to get a long 1/2" coil (75') that I can submerge in ice and drain for instant cooling. I'm not sure about the Newton's law practicality of this, but given enough ice and snow it should work. In Vermont there is ample snow and ice Dec - Mar. If it doesn't work I can always repurpose the coil as a standard IC with sump pump.
A good question comes to mind. Do most brewers use the standard IC set up versus the coil in ice water method for a good reason or because they haven't tried it?