Hi PP,
You forgot one thing. The reason GDN has stated that their reserves will likely be larger, is that the 78.9 bcf comes from the RPS report carried out on Para #1 over 640 acres.
If you work that out Para #2 probably site on the edge of that acreage.
As the have found more gas in Para #2, it wouldn't be stretching to thing the P50 estimates will increase significantly for Para #1 and #2 combined.