I think there's green bleeding on the top of the wall pink and probably you could have a color variation all over the pink... like a huge perlin noise or some grunge.
Also the lighting in the image is on reverse wich tells me there's something near the wall top that's obscuring it.
It's impressive how close your modelling is and the only things differing it from the original are minor details on textures and edge, roundness, roughness or damage. The architecture is so simple and raw, that those are the details that give your image away...
For instance, your window seems almost like contemporary aluminium while Barragan's is clearly rough hand made, probably painted wood/steel and stucco...
Yours is an impressive work so far, but the subject is incredibly difficult.