Disclaimer: I can only speak for the time at Google before the turn of the decade.
The manager determines the new total comp at grant time,[2008] the employee obviously sees their total benefit at vesting time (or typically a little later, as grants usually vest during blackout periods, unless the employee signs up for automated selling at the time the grant vests).
There is none in reality.
In fact, there was a period of probably 5+ years when it was “employee insider knowledge” that it was better to stay at Lx with “strongly exceeding expectations” – a rating indicating you would “meet expectations” at L(x+1) – as with enough insider knowledge you would just be “gaming the multiplier numbers”.
I (ab)used this myself for years.
The numbers to game were numbers set by the comp committee which would, well, calculate things to come up with (different) multipiers for performance ratings at each respective level.
Assume the base comp for L6 is 200k to 250k.
Assume the L6 is “strongly exceeding expectations” which – according to the comp committee – warrants a 1.2x multiplier.
Add in some additional formulas – remember, everything is a precise number to the 3rd decimal multiplied by a manager committee horse trading negotiated blurry bucket summary ratings that need to fit a curve – and you end up with calculations that end up with:
- L6, strongly exceeding expectations, base salary plus x%, bonus +y%, stock options plus z%, total plus A%
- L7, meeting expectations, base salary plus (x-a)%, bonus +(y-b)%, stock options plus (z-c)%, total plus B%
If you were a tenured L6 at 250k (base salary) compared to a fresh L7 at 250k you would do better as L6 not going for promotion.
Of course, Google corp noticed this and corrected things, but it only created different incentives, and as we all religiously repeat after Charlie (Munger): show me the incentives and I’ll show you the outcome.[1]
Looks like you weren’t on my team. 
To be fair, there were (and probably still are) different comp levels for different job ladders.
The way I read the tone of the article, she’s not thinking about compounding, but about enjoying some time off, with a nice backstop by a 17 year senior partner. Lucky him. Or lucky her?
There is not, by the way, an 18-month sabbatical with Google. There used to be a 6 month sabbatical that you could take after tenure of 10 years, IIRC, later reduced to a 3 months sabbatical, and then abolished completely: Google noticed that people wouldn’t just quit but “take a sabbatical” so their stock options would continue to vest even if their salary and part of their bonus was nilled. Given the equity was such an outsized portion of the total comp, “going on a sabbatical” before quitting was just too attractive …
Some (geo) jurisdictions addressed this loophole (for employees), but not everywhere.
Wow. So you approve of them buying back stock (and paying for employee grants) with the company’s shareholders’ profits?
Me, if I were a shareholder, I’d prefer to get the $62B distributed to shareholders instead.
I could then still make the decision to further invest into GOOG, but it’d be my decision instead of GOOG’s which apparently does not know better anymore than to allocate capital into its own stock.
2008 There was a repricing of then stock options (instead of the stock grants later on) because of the GFC. In the middle of the compensation cycle, Google decided to grant more options because the Google stock price deteriorated during the GFC in 2008 or so, to keep employees interested.
In my own ignorant recollection of things, nobody sane in their mind would have quit the company because the stock option grants halved or even became worthless, but who am I to complain about Google extracting a little more money from the market (from the perspective of an employee).
1 Admittedly, there were even more stupid performance indicators, like measuring one’s productivity by numbers of lines of code submitted to the repository.
For the non-coders: this is kind of akin to measuring a baker’s performance based on the number of kilos of flour going into the dough without taking into account how the bread tastes or how much of it is sold.