Ovinomancer
No flips for you!
That's not accurate. While the multiplication is correct, the statement is not, at least not in D&D. Going with 3e, a 3 strength PC can lift 30 pounds over his head, while an 18 strength PC can lift 300. That's 10x stronger, not 6. The other stats are similar. A 3 stat yields a -4 bonus, while an 18 has a +4. That's an 8 point swing, not a 6 point swing, indicating 8x better.
You're making the same mistake that pemerton was, which is confusing the roll on 3d6 for the ability score. The roll of 18 is six times greater than the roll of 3. The ability score of 18 is [undefined] times greater than an ability score of 3.
I say [undefined] because your math is flawed. For one, converting the ability score into an ability modifier changes the structure of the distribution and for two, 4 is actually -1 times greater than -4, not eight times greater. We can't actually say how many times greater the ability modifier of 4 is than -4, but we can say it's 8 steps greater, because ability modifiers are interval data.