The altitude hold feature of my a/p has recently gone awry. It appears that it has lost the ability to pre-select altitude and when the altitude is dialed in while in flight, it blows right through the target number. It is very abrupt and erratic when climbing and descending. It has also lost it's ability to prompt for trim (lower left corner-Trim up, down, etc.). I have checked all of the settings and compared them to my written notes and all is good. It has the latest firmware download. I am suspecting a servo? Anyone have experience with this?