Everyone has thier own interpretations iof what is a effective and safe map.
Clearly though if it causes an engine to go bang, it is not the customers fault, and should be sorted at the mappers expense, IF that is what happened, as two sides to every story.
If you know how to map correctly you know how to map correctly, if you don't you don't simple as that.
There are of course opinions on how much fuel/ignition to add/take away, there are differences in different people maps, some prefer a bit richer to lower temps for example, be a bit safer.
I don't like ahmed's mapping, despite that FACT he knows what he is doing and does do a good job.
Some chips can go dodgy, I had one last week for someone else that checked out ok on the reader etc, the company are VERY big in this stuff and well respected, but the chip just would not work in a L6 it was supplied for.
I did not name the company as it was not thier fault, just very bad luck, they did applogise when it was evident that the chip was at fault, supplied a replacement that was perfect immediately and all were happy.
I know of one particular tuner who has recently been annoyed by a customer who was "over the moon" with his car and the way it went, but the mapper was NOT happy and had the car back for a further day to make tweaks here an there, should the customer be pissed or happy ?, he wanted his car, so did the mapper for different reasons.
tabetha