David, a few warnings ...
Yes, best to do the work at home. You can just take the stack.
Warning #1: the traveling on these is often done without gluing in the paper or card. You take off a hammer flange, and a piece of card flies off. If you can see which side it came from, glue it back on, or you might need to do all of the traveling again.
Warning #2: if you do this job piecemeal, doing the bad ones, then others as they develop, be certain to write the date on any parts you repin. It is only human for the owner to assume that a sticking hammer is one of those you repinned, BUT SO FAR IN MY 42 YEARS' EXPERIENCE, IT NEVER IS. Repinning is the sovereign cure. They never seem to get worse again after the are repinned with non-plated center pins.
Warning #3: if you do the whole set, you'll get the spacing with the strings a little bit closer if you do all the evens, put them back on, and do all the odds. Of course number all parts.
Warning #4 (kind of obvious, though): All those screws into the aluminum rails: take your time and don't double thread them!! Removing with a power tool is one thing, but putting them back in and tightening them down with a power tool is begging for trouble.
Some pianos have the problem with certain parts, and none with others. Other pianos (usually the most heavily used) need to have every single center repinned. I don't think replacing parts with originals from the same manufacturer is a good idea, since the replacement parts might well have the same trouble, just a few years down the pike. The hammer flanges are usually the worst and the first because of the wide range of motion and the physical stress they are under.
It seems to be worse in humid climates.
Use high magnification and a strong light, and you may well see scoring circling the center pins, down at the ends where they touch the cloth. Fragments of plating caught in the cloth, scraping against the center pin, is my theory.
Another way to diagnose this problem, as opposed to other causes of sluggish flanges: the piano plays better when you first sit down to play it -- not so bad after all, maybe just the worst couple. Within a few minutes everything gets worse. This is due to the heat generated from friction in the affected parts, enlarging the center pin diameter. For other sluggishness, like verdigris, the parts would work better as they are played in, or be unchanged, not worse.
I've found it best to explain the problem to the owner, and leave it up to him or her whether to get the whole set done, or just do them as they develop. Depending on the use of the piano, the new ones might develop slowly. Or you can do?? mix and match -- keep track of which you have repinned already, work out a price for doing the others if the owner wants to go ahead. Doing them all at once should be less per note, of course, since you don't have the visits. It's a good time for tactful education, and if you can physically show the scoring to the owner, your credibility will improve. The important thing to stress is that once a part is repinned, it won't go bad again. Done and dusted.
This used to be called "Asian Flu." Nowadays it might be called Korean Flu. Unknown if the Indonesian products have this trouble. You'd think with the pain this must have caused Samick and Friends that they'd figure out what causes it and get it fixed.
By the way, I found doing all the underlevers, both pins, to be the most annoying. All that regulation, and having to lean over to get them out and back in. But I only needed to do that on one piano, practiced many hours a day.
There is another possible issue, as I discovered on a customer's Sammick: wide birds eyes. In this particular grand, many of the repetition levers were sluggish. After taking them apart, I could see the fit was too tight; repinning alone would not have solved the issue. I had to sand the birds eyes. We don't have high humidity in southern Oregon-if anything it's pretty dry.
Alcohol and water will not work to size the bushings or free up things, and neither will Protek (I've been back several times.) On another recently purchased Sammick, the dealer brought the action back to the shop and tried…the problem came back. With the friction/heat issue in mind, I questioned the customer: does it play well at first and get worse as you play it? The answer was yes.On the other hand, I also have a customer with a Kohler and Campbell Sammick. On that one, all the flanges are loose, with many pins walking out.