Yup, that seems to be the modus operandi. I also got email that someone would call me and that I need to use the value by 13 Sep for travel up to 31 Mar 2021.

Now it is silly, but I think this is more of a limitation of the reservation system than SQs own doing. The concept of a travel credit / value doesn't exist quite like some folks may think and that makes it hard for SIA. Ideally, you would either get some voucher code that can be used for the new flight(s) or just enter your old eticket number during new booking and value is applied.

I don't know yet, but suspect that the new ticket you book needs to cost the same or more than the original one, but only time will tell. For our corporate travel, residual ticket value can only be used for flights with same start point where new ticket price is equal or higher the residual value.

If so it'll drive some customers mad, I do feel sorry for the agents having to explain that to inexperienced travelers if it proves true.