Those prices were as of last Sept. Yes I have watched all of Ford parts rise over the last 3-4 years, and when their national inventory gets low with the parts are not in production anymore there is even a steeper increase IMO. For thirty years my group bought about 50k in parts every year and the rise was always there, much more so with the deval of the dollar.
The aux pump has been fine.
Gus, did you replace the coolant when you changed the DCCV? The reason I ask is I not a fan of the gold coolant based on my diesel work and don't think it should be in a vehicle for more then 50k miles or 2 years. I would be worried about it affecting the new DCCV's operation if it wasn't flushed.
Just before I changed the cooling system parts my wife had two occurrences of low coolant temperature, verified with my laptops AutoEnginuity. The changing of the all the parts and including the TS cured that, but it's MO that it was the TS failing.
The aux pump has two jobs: One to pull the coolant from the heater core so it works better (and also pulls coolant from your leaky back of the engine hose assembly); And to assist in cool down the motor after shut down. I would expect poor heater operation if the pump was not working, but I wouldn't expect the motor to run cooler or have a extended heat up if it failed. The only reason I could see a long warmup would be a stuck open TS.
Playing Devil's advocate, I wonder if the leak is more prone now if the Aux pump is not providing a lower pressure within the back of the motor line from the reservoir as it would normally do. Not that it should leak, but if it's slightly compromised the additional pressure may be revealing it's failings.