Sorry, nominally when Google hires engineers they offer a job at 'x' level of engineer but you're not actually hired at that level. What they do instead is wait 6 months and then a committee evaluates your performance relative to other engineers in the company and then tells you what level you are at Google.

The point of the exercise is to avoid hiring people as 'Senior Staff Engineer' (even if they had that title at a previous company) and then finding they only put out 'Staff engineer' or less in the Google equivalent.

They don't change your salary if they effectively demote you down a slot or two but the pay ranges are different. If the committee decides you are more than a couple of levels below what you were hired at they fire you. If you do 'down slot' it means that if you do get a promotion later you probably won't get a pay raise.

Its supposed to keep things evened out. Generally it means they don't successfully hire senior people from outside the company. It was entirely unclear to me how they handled acquisitions of talent.