A further question with HP&L is a question on useful consciousness. Do i really need to know the whole table of useful consciousness with heights and body activity? it seems a lot of numbers.
I can't speak to your exam in the UK, but I can't imagine why knowing the TUC would be of any value at all for flights below 18,000'.
TUC numbers are of interest, and applicable to high altitude flights, but not to light aircraft operations below, say, 10,000'. Hypoxia should be well understood, but useful consciousness isn't really a factor.