That was unclear in the rules as well last year, hence the way the West competition interpreted the rules since no one from SAE was there to make the call. In the rules it states to use the values as a minimum. Never mentioned anything about tubing and such.
I was a cost judge at West both years so far. This year it will be judge based on SAE's clarification that wasn't made last year.
I am sure some teams will still use the actual tubing cost and come out much higher than a lot of others. But overall, the actual cost is only 30 points of the whole event anyways.