@Robert ***********
I answered your question yesterday regarding extension on Non O and visa exemption as you wanted to stay for four months on your Non O.
I understand you ask this question because you want to re-enter later on a new Non O visa.
The best ting for you might be to apply for a one year extension of stay on your current or first Non O visa when you come now. Then you don’t have to do any border crossing to get an exemption for your last month. When you want to come back to Thailand later you just can use your one year extension of stay if you get a re-enter permit and you don’t need to apply for any new 90 days Non O visa next time, you just use your extension of stay based on your first Non O visa. As you’re from The Netherlands your embassy still offer to give you an affidavit letter to confirm your income, so you don’t need to prove this or funds in any other way for your extension of stay in Thailand.