So the gains and losses will be something like this? Assuming SN loose 40 377/1s.
GN
+ 120, - 156, Loss of 36, 9 units
+ 379/0 - 30 x 4 = 120
- 387/1 - 32 x 4 = 128
- 387/2 - 1 x 4 = 4
- 387/3 - 6 x 4 = 24
GTR
+ 156, - 160, Loss of 4, 1 unit
+ 387/1 - 32 x 4 = 128
+ 387/2 - 1 x 4 = 4
+ 387/3...