That "rule" that the data.zip must contain a given resolution, is valid for iGO for WinCE. For Android is little different, so don't worry. Not quite as simple as I explained, but it is close enough and sufficient
Btw, nor I often do not change the phone. Mine is Motorola XPRT almost 4 years old. But, I'm installing Igo very often on other devices (friends, relatives...).