I levelled the frets on a strat neck but, while seating well enough, it required a lot of levelling. This lead to some frets being very flat, too flat for my crowning file. It starts to file the wood (or rather tape) before it completes the crowning.

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Above, you can see some of the worst ones. This much sanding was required to only just touch some other frets. I have a suspicion this may be caused from using a hammer- I had to knock some of them in better but this is the first time I've worked with Nickel, not stainless steel (I know, odd way around) so i may have wacked them too hard and squished them down.

What can I do to fix this? Should I just re-fret?