Making a hop extract with finished beer, not wort. Dry hop alternative.

Experimental method for boosting hop flavour and aroma in already fermented beer. Take one litre finished beer which has reached tg, heat to 60-64c in flask, add hops and any other additions, cover with cling film and quickly cold crash to 4c. Leave a couple of days then gently pour back into the cold crashed beer before bottling or kegging. Good technique or madness? Let me know in the comments please.