A possible explanation for this the originally projected monthly drop in interest rates is exactly following what was projected. The decrease isn't actually done on a monthly basis but instead done every 43,836 blocks. So the third drop in interest rates is to occur after 132,000 blocks are on the chain. So it was projected. using the 9/11 date on the genesis block there would be 131,508 blocks on the chain at the start of the 4th month. If we take a month to be 30 days, then we 7 days from the 90 day marker... about 76% or the way through the month. Taking the current block height of 111599 -87672 (the block for the second month) we are only 23,927 blocks into month 3. That's only only about 54.6% of the way into the month( again being 43,836). So clearly block generation isn't happening as fast as project. I have seen the projected coin creation rates but I am sure they were tied to this. Do you have a link to that?
While the 09/11 date has been a reasonable omen for NoKoin genesis block, it would probably be preferable to use the 23/11 offiicial launch date when the first PoS block was generated (block 793), or even better, a block where PoS difficulty reached usual levels (somewhere around block 20.000). If we take block 793, then block time is ~ 9 % faster then targeted. If we take block 20.000, then block time is ~ 7 % faster then targeted. This might partly explain high orphan rate (especially for PoW).