Assuming your 12XT "touring long" model is a 2008-2009. Adaptive Fuel Value of 89 considered to be somewhat outside the traditional 3-5% accepted value. ECM has learned to "remove fuel" which is shortening the injector pulse-width in CL.
With NO CEL or active/historical fault codes the causes may be:
One or both fuel injectors "weeping" fuel into the TB
Failing O2 sensor
IAC and companion TB port suffering from heavy carbon build-up
Failing IAC
Incorrect breather mod performed resulting in excessive pressures building up internally...crank and top-end regions....which will adversely affect correct AFV being established