I recently ran across a theory that a portion of the superscripts of many psalms was intended as a postscript to the prior psalm. In that arrangement, לַמְנַצֵּ֥חַ (lamnaṣṣēaḥ; to the choirmaster) + optional prepositional phrase should be appended to the prior psalm, and the remainder of the superscript is correctly attached to the following psalm.
This argument is based in part on examples from other poetry that purportedly demonstrate that genre and author are the purview of the superscript, whereas the subscript usually includes technical notes about performance. (The prepositional phrase is something like “with stringed instruments”, “for the flutes”, or “according to the dove on far-off terebinths”[!]).
The key example within the Bible is Habakkuk 3 which ends:
לַמְנַצֵּ֖חַ בִּנְגִינוֹתָֽי
lamnaṣṣēaḥ bingînôtāy
to the choirmaster, with stringed instruments
Obviously, such subscripts have not been widely accepted in the Psalms — I know of no translation that arranges them that way — but people still talk about it, and I haven’t run across a good refutation.
Is this theory still considered a valid possibility? What are the arguments against it?