Basis for Hurt Points

[Norbert]

Boring question maybe, but I still wanted to ask:
Last week, I was beginning to wonder what your basis in the design of the game was for making the Hurt Points start at 29 as their "base".
The increases go in steps of three, I know that (29 / 32 / 35 / 38 / ...).

But I don't know why you get exactly 29 as the base.
Did you have a specific Damage Rating in mind for that number?
Did you say, e.g., an unarmed attack by a character with Body 0 should still make a difference, 0 plus the average of 1d12 is 6.5 or 7?
Four times 7 is 28, so with 29 Hurt Points the victim of four hits would still have 1 Hurt Point left.
Or did you say, well, if you roll a natural "12", add it to a DR of 12, and add an Oomph of 5 (the maximum in the book), you'd have 29?

I was just trying to get the formula behind why it starts at 29, an uneven number. Why is it not just 30 or 40?