Thing to do is try it and see if it works ! I do not see 238 in your lookdown table, you said key 1 returns 238

converting your bytes so

char(0)=$32
char(1)=$33
char(2)=$38

char(0) = (char(0)-$30) * 100 'answer 200
char(1) = (char(1)-$30) * 10 'answer 30
char(2) = char(2)-$30 'answer 8

b0 = char(0)+char(1)+char(2) 'answer 238

compiles but not tested !