JustinVG I think I know what the tuner means, but I'm not sure.
When they install a silent system on an acoustic, they add a hammer stop bar to prevent the hammers from hitting the strings. Sometimes, installers just put the bar in, and leave it in a position that is enough for a lightly pressed key to still fly the hammer, and far enough from the strings to ensure no hammer contact.
But they can (and should) finely adjust the position of the bar so that the hammers come as close as possible to the strings without actually hitting them. Other than the time it takes to adjust, the downside is if you get it wrong, natural settling and variation in the action/body of the piano may eventually result in some hammers reaching the strings and no longer being silent. To be frank, I've heard (and seen) that the most common factory system, the Yamaha SH, is probably the worst offender in terms of leaving the hammer blow distance far off when in silent mode (the spec is like 6mm difference or so).
Short-stopping the hammer with the stop bar also affects the distance of the action's escape mechanism, and this should be adjusted as well (and the various YT installation videos I've seen always omit this step). If you don't, your keydip might become shallower, the hammer might catch on the knuckle, etc., all of which noticeably impacts the feel. From what I've seen, a silent system always introduces some compromise to the action, that's the price you pay to have one single piano you you can play acoustically or silently.
- Not a tech/tuner, just an OCD silent system shopper a few years ago