[SubuSS]

I am guessing this isn't what you wanna hear but, They don't do a post hoc calculation.

It is usually the salary + stock award that will vest over 4 years. For most companies with a flat vest, the total will come to 500k/yr for certain levels.

The appreciation is all yours. Future perf bonuses which will be each 6 months or a year are on top of this. Some companies do adjust for what you're making in that year and cut down the perf bonus (In a previous company I once got a promotion without any stock because our stock had tripled in the time...) - but these companies have a serious growth outlook. Once the stock flattens, there will be a major drain and they know this.