My wife's parents were in Australia with us on 600 visa for 3 months. The visa is valid for a year with stays up to 3 months allowed at a time. My question is that they just left on the 15th of April. If we want to bring them back in May, will that be an issue? Do they need to spend a significant amount of time outside Australia to come back (Like in the US where you need to spend equal amount of time outside the country)? Please let me know. We are plannnig to bring them back around May 15th. Thanks.