Gauge Question

Exactly what I am asking. I bought a set of gauges and they read over 100,000 miles. The gauges in my car read 86,000 miles. So what I am wanting to do is have the new gauges read the same as the ones I am replacing.
 
Ford replaced the gauge cluster on my Explorer before. Even they couldn't (or didn't) mess with it. When I sold the truck, it showed 24,000 less than what it should be. Of course I disclosed it when I traded it in to another Ford Dealer. In fact, there was a small sticker on the door jamb that indicated the speedo was replaced at 24,000-something miles.
 
There almost has to be a legal way. What if the gauges in someones car quit working completly? I know there is legality issue (Doing it yourself).

if it has a digital odometer, when we order a new cluster we need the vin # and miliage and it is pre-programed into the new cluster. if it was an older car wth an analog odometer, the new cluster would come wth a certifaction label that needs tobe filled-out and attached to the drivers door jamb. if you want something wth lower miliage, I'd suggest a junk yard but they may also make you fill out some kinda of paper work on the miliage.
 
I was reading some old Kia recall not too long ago, and they mentioned there are only like 3 main companies in the US that do this service (why only that many, I'm not sure,) and that all the major car companies have to use them to have the digital mileage changed.

An obvious guess would be that there are only a few companies that manufacture the actual gauge cluster components, and those companies hold some sort of patent or whatever on the technology, so they don't allow the dealerships themselves to have access to it.. (think 20 guys who invented this technology knowing the secret to editing it, versus 30 thousand car dealership service dept ex-convicts having access to it.)