Does your home face directly west? Dark render paint colours will always fade. When you look at other homes are they facing the same direction as yours. And how old are the homes and what was the original colour like. You may be looking at a paint that has faded. Our home is facing north. We had to repaint the Dulux acratex render after six years because it had faded. I would think if it was facing west then then the blistering and fading could definitely be a thing.

A friend wanted a black front door 1200mm but the builder would not cover any warranty with that colour door. They went with white.

Yes, your builder is right. Dark black paints absorbs more uv, more light and more heat, so there is a higher chance of blistering and fading. North and West facing walls are the worst.

Dr Retro of Dr Retro House Calls and Dr Retro Virtual Visits via Zoom

Ok thanks for your input guys!