197 ECU Mapping

Why can nobody seem to come to a conclusion about the ECU reverting back to standard form with the 197s?

People have started saying the 197 ECU is pretty much unmappable and you'll need a new one blah blah blah...

After speaking again to my mapper, who assured me that the ECU could not change its settings when i first had it mapped, now they are not so sure? :x

And do i dare say that i think the car is actually a little slower than a couple months back, maybe me just getting used to it.
Gonna go to the dyno next week and get it checked, if it doesnt make near the original after map figure then i'll finally have my answer.

Anyone able to shead light on the confusing subject or know of anything different? Particulary interested in getting another mappers opinion on the matter.