Less development = less contrast, regardless of exposure.
True ISO of HP5 Plus in DD-X is about 650, so you're unlikely to be overexposing normal subjects, and even if you are, overexposure does NOT increase contrast. It does however bring bigger grain and less sharpness.
Doug's advice about favouring the shadows when metering is however spot on. Several of your pics have very long subject brightness ranges, and it may be that the bright areas (e.g. windows or doors in the middle of the composition) are leading to underexposed shadows.
Last edited by Roger Hicks : 05-11-2011 at 23:13.