I was just commenting on your IPA as a point of reference for the hops in your batch.
If by "metric ton" you mean 10 hectoliteres, that is about 8.5 bbls, or roughly 50 times the batch size you are scaling up from. Looked at that way, 2 lbs of bittering hops doesn't seem like that much to me. If you liked the bitterness, I wouldn't worry about it.
As for gypsum, without knowing the mineral content it's hard to say if adding some would be a problem. Can you take some of the water home and do a test batch? It is not likely to affect the perception of hop aroma and flavor though, which is what I think you want.
Another thing to consider is the process - how long does it take to chill the wort, what is the temp of the wort in contact with the hops during that time, and how is that different from what you do at home? Is it possible the dry hops were too restrained by the hop bag to get good extraction? Was the yeast changed, or did they use the same one as you use? What about fermentation temp?