if you check the code, the payout is according to formula: exp(-c*[height/1000]) and c = log5/1000.
in order to avoid too many digits, the dev rounded it to 2 decimals after the point, so you don't get 0.9933286326, but 0.99. This way, the payout will stay at 0.99 for several 1000s, due to the roundups.
according to my computation:
Block Payout
1000 0.99
2000 0.99
3000 0.99
4000 0.99
5000 0.99
6000 0.99
7000 0.98
...
13000 0.97
...
19000 0.96
etc
hope this clarifies your question.
It does, I should have checked the code a little more and did the math.. My Bad
However the Dev should add this info to the OP as the roundup changes the actual reward. as it reads now it's as if it changes every 1000 blocks
but with the roundup it's more like every 6000 blocks, it's a bit deceiving.