Last time, SBS allocated their feeder services to different
residential areas in Singapore.
200 series - ???
210 series - ???
220 series - Bedok
230 series - Toa Payoh
240 series - Jurong
250 series - Jurong
260 series - Ang Mo Kio
270 series - Bukit Merah
280 series - Clementi
290 series - Tampines
300 series - Chua Chu Kang
310 series - Serangoon
320 series - Hougang
330 series - Jurong East
340 series - Bukit Panjang
350 series - Pasir Ris
360 series - Bukit Batok
370 series - Woodlands/Marsiling
380 series- Eunos
390 series - Changi Airport
400 series - Special services???
410 series - Bishan
450 series - ???
Not very sure what the 200, 210 and 450 series represents
where.
And were there service 230, 260, 270, 280, 320, 330, 340, 360
and 380 last time??? 
200 series is mix.. 200 204 205 206 207 208 and 209 serves
different areas.
210 series only 214E/214W which is the now 103 and former 103M. 215
to 219 serves areas such as Bedok South, Tanah Merah and Changi
Village.
450 was from old Jurong Interchange to Pasir Laba camp
400 were indeed special services, Svc 400 remains the same as
now. services 402 was from Stamford Rd to Bukit Timah race
course long time ago. 403 remains the same as now. 405 was frm old
Jurong Interchange to Chinese Garden if im not wrong.