I can well imagine the conversation at immigration...
"You don't have a valid re-entry stamp"
- I do, look there it is
"No, that's no good"
- But Liquorice on AseanNow said it was valid!
"Liquorice said, well in that case sir I must be wrong"
stamp, stamp
"There you go sir, have a nice day"
Should I need to travel during the consideration period, even the period before my existing permission to stay has expired, I will be going to the immigration office for a new re-entry stamp. Better safe than sorry.