the drop is from mining with 12th/s to now mining with 19th/s
If he was talking about his reward per block, then: yes.
But since he is talking about his reward per time: no.
since he is talking about 1600mh/s he wasn't making .1 a day for 1+ months so he is in error as
Average hashrate in last 10 rounds: 3640 Mhash/s does .1 a day....
so since he is in error he is talking about his reward in the last weeks going from .05ish to .025 so yeah that was directly caused by
"the drop is from mining with 12th/s to now mining with 19th/s"
oh and that diff increase of course. mostly that of course. yeah mostly that.