Features Moving After New Alignment????

I was just measuring a fixture using an Infinate Arm with PC Demis 2011 MR1 and a hard probe. I created a new alignmnet at the end of a part program just to check the location of a feature in a different orientation. I dimensioned the feature and noticed that it was suddenly off location by about 2mm rather that the .5mm it showed off before adding the alignment. I went to the CAD and I could see the measured feature change locations on the model by about 2mm from before the alignment to after. I understand that the nominals should change when using a different alignment and the measured location would change to correspond with the change in the axis, but how is the location of the feature changing relative to the model? I'm wondering if this has something to do with compensation software? Someone please help explain this one to me.

Thanks

I was just measuring a fixture using an Infinate Arm with PC Demis 2011 MR1 and a hard probe. I created a new alignmnet at the end of a part program just to check the location of a feature in a different orientation. I dimensioned the feature and noticed that it was suddenly off location by about 2mm rather that the .5mm it showed off before adding the alignment. I went to the CAD and I could see the measured feature change locations on the model by about 2mm from before the alignment to after. I understand that the nominals should change when using a different alignment and the measured location would change to correspond with the change in the axis, but how is the location of the feature changing relative to the model? I'm wondering if this has something to do with compensation software? Someone please help explain this one to me.

Thanks