The table (below right) gives it all to you in four data points.
Runs went up very slightly in April 2018 as opposed to April 2017. They went down by a somewhat more sizable margin in May.
Home runs were down virtually the exact same percentage amount in the two months of 2018 than where they were at in 2017.
The interesting question is what will happen in June. Last year the HR explosion made June the highest HR/G month in the history of baseball.
Will HRs fall by more than 10% this month? Or, possibly, more? Or will warmed-up weather "take the ball for a ride" again? One thing is for sure: Alan Nathan and his "men in tights" don't have any idea, either.