I believe sbi-skip just means they do not give you an upvote.
The down other downvotes those who reward others with it. I believe @marbly said the downvote you receive is a certain percentage of the SBI amount you gave. I once checked it but with me it was way higher at that time. I noticed too I had downvotes several days after each other and next for two or three days nothing.
If you ask me it follows a trail and the percentage of downvotes you receive increase.
He will use some list or trace us by the tag or titles we use.
Like said I didn't receive high downvotes in the past weeks as far as I can remember but will check it out.
π