My 2 pence input:
On FBW aircraft Vref is referenced to VS1g instead of VS like on a conventional aircfraft.
As a reminder VS1g speed corresponds on the polar curve to CL max , situated on top of the curve. Whereas Vs speed is situated downwards , lower on the curve.
VS1g is the minimum speed achievable at 1g which means that the aircraft still flies at VS1g and not in a stall like it would be at VS.
Having said that , I would add that the reference used on FBW VS1g, is a higher speed than VS.
Now if the reference speed is higher, then the increment has to be lower in order to keep the same equation
Vref= 1,3 VS
VS=0,94 VS1g
Vref= 1,3x0,94= 1,222 VS1g
Airbus , authorities rounded up and retained 1,23 VS1g
So mathematically speaking 1,23 VS1g is even higher than 1,3 VS.
Practical example:
Aircraft stall speed : 94 kt
Then Vs 1g = 100kt
Vref referenced to VS would give 1,3x94= 122,2 kt
Vref referenced to Vs1g: 1,23x 100 kt=123 kt
Now which one is higher?
So why some people think that 1,23 vs1 g is a lower speed than 1,3 VS?