This is a very abnormal vesting schedule. I've never interviewed with a company that has a schedule like that. The most common schedule is 25% per year, over 4 years, vested per month, except that the first 25% comes as a lump as the end of the first year. Most companies provide refreshers every year during the comp cycle. Normally during times when stock prices are low for a company, they'll take that into consideration during the comp cycle and give larger bumps.

They're all different. Amazon pays you cash up front with backloaded vesting. Google is experimenting with frontloaded vesting where you get the bulk in the first couple years.

That's amazon. The company I'm at is 25% after year 1, then 12.5% every 6 months. Once you get a few years in it's pretty much just a rolling part of your salary.