Thurkettle says it's more to do with recent history and types of visas you've had previously. Never ever kid yourself that flying in means you won't be denied. There's plenty of people been put back on the flight they've just arrived on!
Doing back to back METVs might raise a red flag, as it's potentially 18 months in a two-year period. You own a property in Thailand. Put yourself in the shoes of an immigration officer or an Embassy official and ask yourself "is this person a tourist?".