While working with Blessed, I stumbled across this gotcha. Where even if I would tell blessed to explicitly move the cursor to the last row, and print text there, it would always print one line above the last line/row.
The end='' part of that snippet is supremely important. Without it, a newline will always be printed after your text, thus bumping up what you printed by a line.
Posting this because a google search matching the title yielded no useful information. I hope this helps.