Furthermore, if the word's length exceeds 7 letters, 10 points will be deducted for each extra letter.

TEd - don't you need some deductions?

typewriters (11 letters-7=4x10=40)

13+1+10+8+12+11+10+13+8+11+8=105 -40=65

stewardesses (12-7=5x10=50)
8+13+8+12+7+11+9+8+8+8+8+8=108 -50=58

Or am I misunderstanding the rules?