Suspect:
SMB221P
(AM SP) 
(AM 806)
Idk whoever edited 221P's status as perm Sv 531 in the first
place, because personally for the past 3 weeks since end-Mar I've
only seen it everyday on Sv 806.
I've never seen it on Sv 531, although i did spotted it once on the
969 x-over slot from Sv 531 before, but that was about 1.5 months
back.
And if anyone did realise after checking out LTA's latest press
release for the bus svcs with improvements made, Sv 806 received a
non-BSEP fleet add
in Mar 2014. So that means it's not 3073E that was
mentioned~
And 221P is still on Sv 806 today too. The bus seems to be on a
full-day slot though. Maybe those that stay in Yishun can
double-verify again?
Is it doing Feeder 806 throughout the whole week? As in
weekdays, weekends, public holidays?