Update: Okay, so you CAN set your second or third phone to receive the SMSes on MultiSim. You have to make that phone the "first phone". To set it as the first phone, you have to key in *136# and press Send/Call. Thanks to Samuel for pointing me in the right direction. A small boo to M1 Customer Service who did not mention that tidbit when I called about not receiving SMSes on my second phone.
So I was thinking, wouldn't it be cool to have one mobile number, but be able to use it on different phones? The M1 MultiSim service seemed like a great idea so I signed up and paid the monthly subscription.
After a few days, it occurred to me that I wasn't receiving SMSes on my secondary phone. A call to the customer service centre confirmed that yes, only the primary phone can receive SMSes.
It also says so in the FAQ:
"Q5: Can I receive SMS and MMS on the 3 phones? A5: No, only the 1st phone can receive SMS and MMS."
Er, not very useful, is it? I mean, SMS is such an important part of my phone experience, why would I use a service that only lets me use my number for voice calls and data on multiple phones? In fact, I reckon I use SMS more than I use voice these days.
Singtel's MultiSim service is the same:
"At any one time, all Multi-SIM cards can make outgoing voice calls/video calls/SMS/MMS. Only 1 of the Multi-SIM card (term as Preferred Card) will be able to receive voice calls/video calls/SMS/MMS. ALL the Multi-SIM cards@ will be able to use data simultaneously. So, you can make a voice call while working / surfing using a PDA/laptop/Blackberry."
Starhub has MultiSim too, but for theirs:
"Incoming calls, SMS and MMS will only be sent to your assigned primary handset."
So much for the one number, multiple mobile phones lifestyle.