With you 100% on that one 16 Blades.
We have to call slightly above/below when your data-block indicates more than 20 feet from the glidepath. Begs the question, what's the height of a C130 from nose wheel to top of tail?
Not really sure why we don't use the old CR62 criteria which are still published in JSP552. As you say the numbers do leap wildly up and down the GP at times. By watching the blip rather than the data-block you get a much better feel for the true profile of the aircraft.
Here's another can of worms. How would you feel being constantly told you were slightly above or below glidepath on an RPAR monitored ILS?
Cheers,
LXGB