Original HP of your car is 120. Tuner said that he can make 180.
The remap is classic copy/paste job. Your friend copied the maps from ORI 150hp software to your car. This remap is limited at 150hp. Ask your friend how he calculated that you have 180hp.
Who ever did this remap really had no idea what tuning is. He made A LOT of mistakes. My advice is to put back the original software.
This is the ORI file for your car-
http://www.ecuedit.com/opel-vectra-c-1-9-cdti-t2990I posted it so everybody can see what he did and have a good laugh.