UPDATE: I finally got fed up with the constant adjustments on my Elan Mira. There is a certified service provider in my area (Orange Co., CA), The Steno Doctor. I called their office and was informed that Stenograph trained nationwide tech/repair providers last year on this issue. Apparently, there's a doo-hickey in the Mira that gets pitted over time and the stacking starts. A certified repair tech replaces the doo-hickey, does a cleaning/maintenance and your Mira will be good to go.
To find a Stenograph-certified service technician in your area, go to Stenograph.com, click on Support, then Service Providers.
I hope this helps.