Normally, I've been able to raise or lower the IAS in the autopilot box in 1-kt increments using the mouse (I fly passenger jets mainly). Recently, I've noticed that when you click the IAS box, the IAS sometimes increments by 10 kts, rather than 1. It doesn't do it when displaying Mach numbers - these increment normally.

Anybody have any idea why it might be doing this? Thanks!