Can use see the volume of water that has run through the softener between regenerations? If so does it match an estimated total of 60 gals/person/day? If way over that you may have a water leak sufficient enough to cause the unit to have to regenerate every night.
If no leak or excessive water use, can you reset the control valve back to factory settings, naturally after writing down the present settings first so yu can reprogram it later?
The service guy should have checked this stuff but maybe he doesn't know anything but changing out parts or more likely he didn't think about them.
You have gotten great service out of ther softener, 12 years, when most of that brand and their sisters usually have expensive problems in 2-5 years.
If you decide to replace it, I suggest a correctly sized softener based on the constant SFR gpm your family size, number of bathrooms and the type of fixtures in them requires, to be greater than the peak demand gpm as to how you use water in your house. I suggest a softener with the Clack WS-1 control valve. You can learn all about correctly sizing a softener on my web site.