Possibly to try and bring the colour issue into perspective, from a modern point of view, which will show why although it says Red on the tin what you get is different.
To paint three Chieftain tanks we were issued three tins NATO green and one Matt black. Boss's tank first painted comes our brill, next one less paint so thinned with petrol (thinners were a fantasy beast), comes out a thinner looking colour but still looks ok, last tank paint nearly gone, so thinned with petrol again, very washy thin appearance but still ok. A few days in the field and the tanks with thinned down paint start to have the colours fade easily, while the unthinned still looks ok. A few days in the sun and all three look very different although all painted from same paint, same day. Further if the matt paints were not stirred for about 8 months!!! you ended up with glorious gloss, so really paint is so variable, 100% decisions just do not exist.