This is what I remember reading:

from THREAD: RE: Tunings, String Bending and Intonation

"Strings can go "false". This means they change their pitch as they are sounding. Bending and constant retunng seems to make my strings go false sooner. All guitar strings wobble a few cents as they sound; but if you can hear the difference in pitch as a note sustains, change that string. It will be impossible to play in tune with it.

I have started using 80/20 bronze strings instead of Phospher Bronze and they seem to hold up better under a lot of retuning. It could be the brand. The Phospher/Bronze I use are D'Addario whereas the 80/20s are John Pearce."

Hope it helps!