S-A AW series of hubs:
Gear 1 to 2: 7.4mm
Gear 2 to 3: 11.2mm

Another thought: Gear 2 must be aligned. Gear 1 happens when the cable is taut. Gear 3 happens when the cable is slack.

Of the current production, the RS-R*3 series, the S3X hubs and the CS-R*3 series Sturmey-Archer three speed hubs have different cable pulls than the AW series hubs.

HTH