The "Purchase property" reason also triggers the transfer to show up as international/foreign together with "Funds for long term stay in Thailand". If it shows up as international or not depends on the receiving bank. Same with the bank code.
It's for every 1 year extension. It's done in a few minutes as long as your documents are in order. At Chonburi immigration in Jomtien, you can pick up your passport next day. Thats the only difference.
It's up to the branch what documents they want. In many provinces they are never asking for the yellow house book. My comment was about Bangkok Bank and their requirements in some provinces.
You're totalt correct. Do it the way immigration and your bank requires and your life will be much easier. Strange and sometimes illogical requirements is not something to have an heart attack over. 😎