[Stephen Tu]

GIB seems to have some holes and overlapping ranges in the notrump ladder after 1c-p-p-?:

1nt shows 11-14.
2nt show 19-20.
This much is fine, fairly standard. Maybe some slight debate whether 2nt is 18-19/18-20/19-20/19-21 but 19-20 is probably ok.

However:
1c-p-p-dbl;
p-1h-p-1nt

shows 16-20?? and still shows 2-4 hearts. It should probably deny 4+H in principle, and range should be 15-18 or 15-17.

Also,
1c-p-p-dbl;
p-2d-p-?
Here things are really screwy. 2d showed values, 10-15, so 2nt/3nt should be able to be bid on less strength. but 2nt show 19-21, and 3nt shows 22-25?
I think 3nt should probably be 15-18, 2nt = 13-14 with a club stop?

And, over a major:
1s-p-p-dbl;
p-2d-p-2nt

currently shows 19-21? But balancing 2nt already show 19-20, this logically shouldn't be same range, this sequence should probably be 17-18. The balancing 1nt should probably be something like
12-16 over a major, dbl then 2nt 17-18, if following what Mike Lawrence's book on balancing recommends.