Coding-Decoding - Letter Position Arithmetic

Pattern: Alternating subtraction and addition of positional values of letters: $\text{R}(18), \text{A}(1), \text{S}(19), \text{C}(3), \text{A}(1), \text{L}(12)$ $-18 + 1 - 19 + 3 - 1 + 12 = -22$

For SIMPLE: $\text{S}(19), \text{I}(9), \text{M}(13), \text{P}(16), \text{L}(12), \text{E}(5)$ $-19 + 9 - 13 + 16 - 12 + 5 = -14$.