I understand there aren't any fortune tellers on this forum, but if you have experience, either personally or with friends, of leaving the country(my reason for leaving is to show them my retirement visa in Thailand expires 3 days after I return to Singapore) and returning(see below), which of the three possibilities is likely, based on my original visit of 90 days: the same 90 days, extended or shortened?
From ICA:
You may wish to note that the grant of visit pass (90 days) upon arrival is meant for you to stay legally in Singapore, once you leave the visit pass is ceased to be valid (voided).
You will be given a new visit pass upon new entry into Singapore.