Permitted variations aren’t close when worked out (10)

I believe the answer is:

tolerances

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'permitted variations' is the definition.
(tolerance for variation in a machine part)

'aren't close when worked out' is the wordplay.
'aren't close' can be anagrammed to 'TOLERANCES'.
But, I'm not sure how the anagram is indicated.

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I've seen this clue in The Times.

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