Dak435, I am pretty sure that you will find that an approach speed factor of 1.23 is acceptable when applied to Vsr ie 1g stall speed. The factor of 1.3 was applied to stall speeds measured as the minimum reached during the stall manoeuvre. The change from minimum speed in the stall to Vs 1g started around the time of the A320 development.
While FAA special conditions were applied for a number of years it seems that the issue was formalized after the issue of the NPRM linked below.
1-g Stall Speed as the Basis for Compliance With Part 25 of the Federal
Essentially 1.3 Vs0 and 1.23 Vsr are about the same speed.