Digi-Tec and supercharger belt

[Berthil]

Today I went to Motortrend Maasmechelen (official Digi-Tec dealer for Belgium) to exchange the special Bosch spark plugs for newer ones, and to clean the air filter as they instructed me 5 months ago when I got the Digi-Tec tuning for my MCS from them (15% pulley, ECU remap).

I was impressed by the power gain, but a month after I got the Digi-Tec tuning I got a MTH tuner file and the power gain was even more.

I'm a honest guy so I mentioned to Motortrend that I got the MTH software so they should not upload theirs (he didn't know MTH?). He wen't of to have look at my engine and was back within the minute to tell me he couldn't do any work at my MINI, and then told me the supercharger belt was running of the pulley! If it would run of completely my engine would be a mess, he said. He told me to go to the BMW dealer to sort it out. So I asked him how it is possible that a software change can cause a supercharger belt to run of partially. He didn't have an answer, he only told me he wouldn't touch my MINI anymore.

So I went to my BMW dealer, he had a short look at and walked away briefly to come back with a special lever, placed it carefully at the pulley belt and pushed the belt back in it's place. These things sometimes happen he said, could be small rock that got caught inbetween the belt and pulley that causes these things, nothing was wrong with it.

So now I wonder, did the guy from Digi-Tec knew that the pulley belt runs of easily with Digi-Tec tunings because he was back so quick and is he using my MTH software as an excuse to save him work and costs? Why do pulley belts run off anyway?

I also drove back to the Digi-Tec tuner to ask him of he now would change my spark plugs, but he didn't want to do that.

Is this normal behaviour from a tuner? Anyone had experiences like this?