As for the amount of bonus rewards, I believe the reason is referral bonuses - if that address, that you use as an example, has many referrals, they will get 5% of every referrals contribution. So that’s an important factor to take into consideration. In other words, if 100 people all contribute 10 KSM, they could all get 100 different amount of AIR rewards because of the referrals.
Regarding the NFT bonus, it was mentioned that the Heavyweight bonus would be given to the first 1500 people who contributed 10 KSM or more. If you contributed the very first day, you should be guaranteed that reward.
You can check if your wallet address is on this list then you are among the top 1500.