Renewed my visa extension (retirement) at khon kaen this week. No problems as paper work was in order. There was just on thing and not sure if this is normal or only in khon kaen. My extension was due for renewal on the 1^st of October (I went early) but my passport expires on the 26 september 2016 (next year)so they only extended my visa till the passport expires. Just wondering if this is normal as I only loose a week but if my passport expired in say six months it be worse, I have to apply for a new extension when I renew my passport not just transfer the extension as I have read on other threads.

Yes it is normal.

Extensions are given up to the expiry date of the passport if less than one year.