Correction!
Apoc-W. has the gist...
While you are right in general, this enquiry highlights the exception to the rule.
The principle of performing a CWE to extract codeine or dihydrocodeine from a combination medicine containing paracetamol / acetaminophen (APAP) is based on the simple fact that while the codeine dissolves readily in water, APAP does not, at least not at temperatures at or below room temp.
So, as certain folk have difficulty with tablets and capsules, there are certain medicines that contain a version of APAP that has been altered to dissolve in cool water, namely solpadol type products which offer an effervescent version of the drug, or lemsip type cold remedies.
These medicines are inappropriate for performing codeine CWE's as there is no way to filter the APAP as everything dissolves.