Dev, can you please explain the math to me on this POS of yours?

PoS Variable Interest (from last PoW block):
Month 1: 365% Interest (< 30 block days)
Month 2: 100% Interest (31-60 block days)
Month 3: 25% Interest (61 - 90 block days)

If I buy 1000 coins, how many will I have after the third month?