I believe this was done to eliminate the 4 year cliff. There is no refresher between years 1 and 2 so same percentage slight raise with growth. Then you start getting stacking refreshers. When I was at google including sign on bonus I got basically a 0% raise between years one and two and then a 35% raise the next year due to growth plus stacking. I left before my cliff when I would have seen a 20% drop due to the lack of first year refresher. They have essentially bumped up year 1 and 2 salary while eleminating the big bump for year 3 and corresponding drop for year 5.