We need more blocks and more luck

It seems that BTC per THs is reduced from 0.00035732 on April 26 to 0.00021599 today. But the number of blocks is 2 on average. I am not sure whether it's entirely due to difficulty or not.
This reduction isn't really difficulty related, but rather luck related. Not sure what time zone you are in, but it's possible that you saw two blocks today in your time zone today, and 3 blocks in your time zone on April 26.
Kano.is shows 2 blocks found on both days in UTC time. If you are going by UTC time, it's probably because April 26 had a lower hashrate and better luck than today had.
Difficultiy can make a difference, but (probably) not a 40% difference.