Okay as
@Fero *****
correctly pointed out there is NO SEASONING of the 400K baht funds for extensions based on supporting half thai children.
AND
ONLY chaengwattana requires people to keep the funds in the bank during the under consideration period, update your bank book on the date you go back to get the extension.
SO if they O/P isn't in Bangkok I'd say they're fine to use the money BUT there's nothing wrong with the advice to wait out the under consideration period before you touch it. Better safe than sorry ๐