Not too sure about that per se. Narcotics take time to kick in. If anything taking benzos too earlier would cause someone to "forget". I would be more concerned with the risk of vomiting and other side effects of the hydrocodone over "forgetting" although it is possible too I suppose.
Back to OP's question: a few things (1) yes it does deteriorate although medical journals say it takes a
very long time to truly not be effective (See:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7040264/ and
https://c3-preview.prosites.com/241033/wy/docs/Catalog/Expired Medications 2012.pdf) however (2) it would greatly increase the risk of vomiting. I plan to follow the PPH protocol exactly (or as extremely close as possible) to avoid any failures or mishaps. The point of the tylenol/paracetamol (they are the same thing, Tylenol is just a brand name of Acetaminophen) is to help with any possible pain/discomfort. Also hydrocodone can cause chest tightness especially if there is no tolerance so it could end up causing more discomfort.
The SN Bible has a pretty good discussion on the protocols but the PPH guide is what I plan to follow.
I hope you find what you are looking for and find serenity & peace.