The chip's phase measurement transer function has a positive slope for
phase
angles less than 0deg and a negative slope for phase angles greater than
0deg. So it seems to me that resolving the 180 deg ambiguity is just a
matter of knowing which slope you're on. This might be done by switching
in
a small known reactive component and observing which direction the phase
output changes. Once you know which slope you're on, I think you're home
free...no??

Do it the way you want to.

W4ZCB