L3+ buyers got bigger coupon because there were huge price differences for THE SAME batch. Some payed about 1500, when some payed 2000$ (same delivery date). That was unfair and bitmain offers some compensation.

The only reason you got 125$ per D3 is because some idiots complained that D3 wasn't making 80k per year like they saw on the calculator. You can even sell those coupons for cash/crypto if you don't want to buy bitmain's antminer again. And your are still complaining !