Since it doesn't matter for the Op. Amp. itself, the components presented as "single-supply" commonly relate to rail-to-rail input/output devices, which operate on lower total voltage supplies. If the input and output signals and their DC offsets operate within the limits, everything works fine regardless of the power supply (single or dual).
Since they are equivalent, "total" operating voltages are normally the same:
But in this INA datasheet, different values are presented:
At the page 20 of the datasheet there are detailed informations on input voltage range, including the Vref pin, but I could not relate this with the asymmetry in supported supply voltages. The difference is even higher for the AD8227.
If the reason for the different lower operating power supply voltages was a reliable Vref, it would be harder to use the INA with single-supply, and not the other way around.
Question: any idea on why can't this device work with ±1.1V?