Salts are legit and well established,the same can't be said for the latter.
I've heard this story under similar circumstances many times when engineers simply revisit time and time again when the panel needs replacing.
Your panel SHOULD of been replaced!!!!.
I'm with gts here "as always" he knows his stuff, and like me swear by the reliability and user friendliness of scantronic.As said you could always ask for the master code or get them back to change or give you the code then f**k them off.
Don't pay them either,say you put cheque in post then boot him out.
Can't believe you have let this carry on :(
e manno, January 2014