1.90 is possible
i took bus from kallang mrt to pasir panjang, within 40 min,
after alight, i get on another next bus, from pasir panjang to
katong, from katong another bus back to kallang,
as long during this jorney did not repeat same bus number,
within 2 hrs, last few trip can possible be 0 fare, same day check
at machine can reflect travel detail
next day those 0 fare will not reflect on machine,
also tried, kallang mrt till boon lay mrt, shopping within 40
min, take bus 30 back till tanjong rhu, change 12 back to kallang,
bus 12 possible is 0 fare