I.G.I, many here have advocated shooting at box speed but unless one has tested their meter, metering technique, apertures and shutter speeds for accuracy you can't be sure you are actually getting a box speed exposure. That is why I advocate adding some exposure, up to a stop from box speed to lessen the possibility of underexposure and loss of shadow detail. Any small overexposure will cause no harm. So shooting at lower ISO as you mentioned is a good idea as far as shadow detail is concerned but robbalbrecht's color problem is likely due to scanning errors.

I optically print Ektar and never have the blue shadow problem any more than any other film. Shot in the sun, any film is likely to have a little blue in the shadows from skylight but Ektar, being a high saturation film, may enhance this.