Question after Water Pump replacement

[dav9515]

So, i had a very reputable and well known shop here in CT do my Water Pump and Thermostat replacement. I brought in the parts including 3 gallons of Porsche Coolant and 3 Gallons of distilled water. When i got the car home, i opened the trunk to find 1 unopened Gallon of coolant and 1 unopened Gallon of distilled water.

i thought this was weird assuming if you properly flush the coolant it should take more than the 4 used to fill the system. Looking at the radiator cap area today it was wet around it and the cap was not properly on but the carpet was not wet so it didn't "leak" a lot. However the fill level is below the min mark and upon inspection of the coolant it appears to have been mixed with the old coolant (red porsche - New + Green/Yellow - old = an orangey color now)

So my question, i didnt specifically state to the shop i wanted the coolant "flushed" but i would have assumed in doing a Water Pump replacement and me providing adequate supplies they would have completely drained the system and refilled with new. Is that not normally the case for WP replacement? did i need to specify?

This shop is a very well known race shop and had numerous full track cars as well as street cars they were working on so i felt good leaving my car with them but this is a real head scratcher for me.

for details the car is a 97' base so with the 2.5L motor. any input/advice? should i just use the remaining gallon of Red coolant i have to top off the system and keep checking to see if i need to add more?