Is Zillow or Google responsible for the incorrect positioning of "house markers" within each block?

Example, I examined a neighborhood I grew up in, Waterloo Iowa 50701, where I notice that themarkers for a block of houses are all bunched up over the first two or three houses of a string of five to twelve. See from Euclid to OrangeGrove/ from Campbell to Third. Specific instances: 623 OrangeGrove, facing west on the NE corner of Kingsley/OG has its label attached to the house 1037 HomePark, whose own label is too far east at approx 1017 HP. Similarly, Campbell 709-735 are all hovering over 709-711, leaving the west half beyond the alley unlabeled.