Hi,
good point, your statement is correct.
I am not able to answer you with precision because I have them (lines) in some conditions others not, I was even able to with same amount of chars on screen have different behaviors with different piece of hardware!
Bottom line, if they are not annoying don´t bother.
I will try to really dig about this ASAP and about the delay, never worried much with it.
Cheers,
-KV