Bridgeport interact 520 Wear compensation problems.

[mustangillusion]

I have a bridgeport interact 520 mill with a heidenhain tnc155 control. I used mastercam v9 to make a program to make a flange with an ellipse (oval) in the center. I programmed it with wear compensation built into the program. The ellipse is .03 too small all the way around x should be 3.5 and its reading 3.46 and y is suppose to be reading 2.42 and its reading 2.39 I put -.01 wear compensation in for the tool that makes the finishing pass on the ellipse. It seems to adjust correctly as long as I stay below -.005 but not above. This is all happening just by letting the program run it self from beginning to end. but when I do this start it at the begging (block 1) and then press feed hold-stop-go 61 (block that begins the finishing tool on the ellipse) then the wear compensation works as it should. Should I be using a differerent type of compensation? The tool im using is a .5" endmill, measures out to be exactly .5". It also seems like when I finally do get it to read right, after making a few parts and going back and forth between two programs that the wear compensation just quits working. I thought about just trying control comp and putting in the radius of the tool and see if this works better on this machine. Please help if you can.