I think many people would see no increase and assume there was some special mechanism needed to enact increases which hadn't happened in that particular year. Whereas a $1 increase clearly says "someone evaluated this and adjusted it up only $1". The analogy of a 10 cent tip vs. not tipping is a good one; the person who doesn't tip for a full meal is being a cheap asshole, but the person who leaves 10 cents is being a mean-spirited cheap asshole.