Script does run, as you said

However, results seem erratic and it's probably not a script issue. There are many uncertainties in my preliminary setup... early stage of controller development... button hold-down still far from perfect.... etc.
It would be a great help for trouble-shooting if I could insert a few text messages in the script to track what's happening during tests.
Would it be feasible to add a basic print text to lcd function, just for testiing?