Hi aj,
This highlights the ridiculous problem of copyright! Due to copyright laws, nearly all reflexology charts are slightly different, confusing I know for students!! However, I don´t think you can go wrong by using your A & PH knowledge - I´ve always found that logically mirroring the body onto the feet will usually put you in the right place as regards the correct reflexes. Think where your heart is - yes mostly on the left but slightly central too so can overlap onto the right foot reflexes. Also as stated by others, there are other things in the same reflex area for instance the oseophogus, ribcage, thorax, vena cava, lungs, as well as a network of important valves and blood vessels.
Remembering that we are not to diagnose is really important. I´ve always found that reflexology always helps the body, never works against it i.e. working the reflexes and dispersing ´crystal´deposits can only benefit the client in a positive way. Of course this does not mean overworking the reflexes either.
A thorough client consultation should also make you aware of any existing health concerns and if these are ´backed up´by your foot chart then have no hesitation in referring the client back to their health professional if you are not happy.
Many a time I´ve suggest they go and have a general ´MOT´if I´ve suspected their ´heart reflexes are overloaded with crystals´ i.e. ask them to go and have cholesterol check/blood pressure check etc.