asked one IO before about AR-11 and temporary moving

The IO told me it's not necessary to file AR-11 if temparory moving less than 6 month and keep your permanent address. In US, many people has two or more addresses, for example, consultant, contract work. So your situation is easy to explain, this is grey area.. If you want to file AR-11, you can file it anytime and can find reasonable excuse to explain it