In a certain code language, 'BOSS' is coded as '21967' and 'DEAL' is coded as '19192414'. How will 'GAIN' be coded in that language ?

16231612

1   2    3    4   5    6   7     8    9  10  11  12  13

 A   B   C    D   E    F   G    H    I    J    K    L   M

 ↓    ↓    ↓    ↓    ↓     ↓   ↓    ↓     ↓   ↓    ↓    ↓    ↓

 Z   Y    X   W   V    U   T    S    R   Q   P    O   N

26  25  24  23  22  21  20  19  18  17  16  15  14

*************************************

THE LOGIC FOLLOWED HERE IS :

B → (+4)  → F → (opposite positional letter) → U → 21

O → (+3)  → R → (opposite positional letter) → I → 9

S → (+2)  → U → (opposite positional letter) → F → 6

S → (+1)  → T → (opposite positional letter) → G → 7

AND

D → (+4)  → H → (opposite positional letter) → S → 19

E → (+3)  → H  → (opposite positional letter) → S → 19

A → (+2)  → C → (opposite positional letter) → X → 24

L → (+1)  → M → (opposite positional letter) → N → 14

SIMILARLY

G → (+4)  → K → (opposite positional letter) → P → 16

A → (+3)  → D  → (opposite positional letter) → W → 23

I → (+2)  → K → (opposite positional letter) → P → 16

N → (+1)  → O → (opposite positional letter) → L → 12