It is usually the neopreme gaskets on the screws that over time dry out and crack. this leads to leaks.
I'm not sure what a screw shooter is.

what we do is to increase screw size and replace the screw and gaskets ( they come together ).
one person unscrews and cleans the area, the next person
installs the new gasketed screw.
two drills, two people..cool mornings.

if you over tighten the screw it will mangle the gasket
it takes a few screws to get the hang of it.
what you want is for the gasket to plump out but not
be compromised.

I don't see why you couldn't do it. go to metal roofing company with a screw you have removed so that you can get
a larger size..just go up one size.
buy more than you need and return what is left over.
wait until you get a pretty day and don't go on the roof
while the dew is still on the roof as it is very slippery.
and don't drink a beer until you are finished for the day.
it is nice sitting on the roof drinking a cold one..great view, job well done.

be careful up there, and best of luck.

I have learned a little about metal roofs in the last year and I am still trying to decide whether I want one. The main division is between panels known generically as "R-panel" and others that are "standing seam". The latter have no exposed fasteners. They are flat panels except at the edges so they may be less wind-resistant. The seams are crimped together or lock in some other way. "R-panels" and the like have exposed screws that fasten the panels down. The fasteners should be in regular rows across the panels. Can you see them when you look at your roof? Each one of these screws is sealed by an organic seal of some sort. I understand that in times past, this was neoprene. If you have a roof installed today they should be EDPM. The latter is more UV-resistant and lasts a lot longer. I don't know when the material was changed. After a time, the seals break down and water starts to leak into the wood that the screws are driven into. The wood rots, the screws get loose. When the wind blows, well, you get the picture.

The screws can be replaced, but I don't think it is often done for houses. I talked with a roofer a couple of months ago who said that he has done it for commercial and industrial buildings so I don't know why it could not be done with residential. I suppose you could pull a few and inspect the seals. I think that 13 years is pretty early for failure.

DIY should be pretty simple if you don't slip off the roof. I don't think you should try to get on anything more than a very low-slope metal roof, and maybe not any metal roof, without a properly-attached safety harness. They can be very slippery. Let me be very clear. Falling off a roof could be a major bummer.

Google "R-panel" and "standing seam" look at some pictures and confirm what you have.

According to my opinion aluminum or copper, metal roofs offer some of the best protection for your home. They withstand high winds, shed snow and rain very effectively and are fire resistant. Some people fear that hail may put dents in a metal roof, but many roof metal materials guarantee no denting. Another concern is that lightning may be attracted to a metal roof, and is more likely to strike the house but this is unfounded. Metal roofing is generally more expensive than asphalt roofing, but cheaper than tile or slate roofing.

it is not uncommon to change the screws
metal roofs have a long life, the gaskets
on the screws have a much more limited life.

this isn't something I'd hire a roofer for
unless there were other issues.
I'm hands on, so it isn't a job that I would
have a problem doing. but if you feel it is above
what you are comfortable doing, hire someone.

when we bought the screws on the roof we are changing
I called every metal roofing company locally
and checked with the box stores hardware and lumber
companies. no edpm..guess we could have ordered online,
but time was short.

best of luck.

Hire someone who is qualified to work on metal roofs.
Ron