Flat Robert Louis misses out on, having no advantage (4-7)

I believe the answer is:

even-stevens

'having no advantage' is the definition.

'flat robert louis misses out on' is the wordplay.
'flat' becomes 'even' ('even' can be similar in meaning to 'flat').
'robert louis' becomes 'stevenson' (author Robert Louis Stevenson).
'misses out' suggests deleting specific letters.
'stevenson' with 'on' taken out is 'stevens'.
'even'+'stevens'='EVEN-STEVENS'

I've seen this clue in The Times.

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