My STEC 60-2/Aspen GPSS was a great upgrade in 2015 from the old one-axis autopilot and HSI but it has always struggled to follow approach turns, always swinging further and further outside the desired course and requiring me to go manual briefly to get back on course. The turn coordinator seems limited to only 75% SRT. Is the TC sending its 1v signal too early, is there a mechanical issue limiting control surface travel, other?