This is clearly a change from the 2012 rules. The rule was clear, explicit and unbending to interpretation, the bottom of the tailpipe had to be within 60cm. With a DB6, Kent or Honda, the DB1 hytech header (designed under pre '86 rules) on a post '86 DB6 is illegal and has to be modified. Mine was angled down slightly to make the limit at the high end of the ride height range. On the Honda, HPD delivered it as the DB1 car was (their test mule) and the original Fit engine rules did not include the tailpipe height restriction so technically they delivered a legal part. Now, for 2012 DB6 - Honda owners had to angle them down to 60cm to the bottom of the pipe.
With this rewrite if your interpretation of the 'box' is accurate, then we have to angle them down another 2". Any height is fine, just freaken pick one because by the time I haul the car to a fabricator, buy the material, make a new support I've just spent a weekend's budget on chasing rules. Not cool. Frankly, the proposed rule is very open to interpretation the way it is written whereas the current rule is much clearer. Either state the box it must fit in with the new language or pick the bottom of the pipe as it was (or chose 65.08cm as the top of the box). Just don't leave that part of the proposal subject to varied interpretations.