Dave, answering your quiz accurately is impossible. Each time you added water and flushed, a different ratio of coolant was drained out. Why? Because of the coolant that was left in your IC system/circuit and mixing with the added water at an unknown factor/ratio because of the shared OEM surge tank. To get all the coolant out of the IC system, you need to open up the lower hoses to the Heat Exchanger and or remove the Heat Exchanger from its perch and dangle it down and open its draincock. And then, to really get it all out, compressed air(10p.s.i. or so). This procedure is not in the service manual. All it shows is the HE dangling, to drain for removal. Yes, a huge PITA. Fortunately it doesn't have to happen very often. Did I mention that you need to remove the front bumper to do all that? When I split my systems up, and added a Bigger HE and small fill tank, I plumbed in a tee in the lower hose and added a new draincock, so the next time I want to flush the IC circuit, I can open the new drain below. Those that are using the Supercooler have a draincock.