Wall in middle of tile floor: grout lines don't match
This is indicative of a poor initial layout, perhaps due to inexperience. An experienced tile setter takes note of the areas where defects (like grout lines that can't line up, small or thin cuts, discolored tiles, etc.) would be most visible and makes sure things are perfect in those places, hiding the inevitable problems elsewhere.

If the tile had been properly laid out before setting it, the lines would be perfect across the open areas. Small differences in tile spacing are normal but are normally hidden by "pinching" or "spreading" the grout lines in places where it won't be noticed. 


  should I tell my installer to do it over?



I would, or I would insist on a significant discount due to lame installation then hide it with an area rug or something...


This is an example of why you should hire reputable contractors who are not shy of providing references, or hiring out of the local guild. You get what you pay for sometimes...