I only had a 2 months visa when i applied and i had my ticket back home bought for 6 months in thailand. Never been a problem and I have been here 5.5 months
i did the same thing you are asking about when i was in Phuket. It worked but i had to go back to the same office a month later to get the visa. They will only have your visa under consideration until you come back. So yes you can do it but it may affect your travel plans