I've seen them overused plenty. Slews of footers all linking back to the same page on county / town names.
Have you tried the text de-linked to see what the rankings difference is? Is it the fact that it's anchor text that is boosting it or just the presence of 'type of' widgets 'location' on a page that already has a strong trust factor for 'widgets'?
Added: I think that links to the same file were devalued years ago because it was a popular spammer's trick, but I could be wrong. But, why would you want to link a page to itself? Seems like something you should build into the algo to be ignored because there'd never be a 'legitimate' reason to do it.