I noticed that my coolant levels were going down.

What is your question?

I can see where coolant is leaking from two hoses and took it in to be serviced. The est. came back at just over $900 to repair the Gasket-Thermostat, hoses, and coolant system service w/ extended life. Is this all necessary. I guess what I'm asking, does the gasket/thermostat need to be replaced if the collant is leaking from the hoses?