No, they are not. Neither can I think of any instance of --> ∅ sound shift in Japanese.
非常 not + ordinary
emergency, extraodinary, very
use of 以上 in sense of over derives from a typical end remark, "Above has been the xxxxx."
In fact, the essence of Sino-Japanese terms as the two is the combination of characters rather than the pronunciation. This pair, hijō and ijō resemble each other only because completely different characters can share the same pronunciation.
From what you say, these terms were coined starting from Chinese elements, somehow like "photograph" that was coined from the Greek elements photo "light" and graph "record". So, of course, the kanji-s give the clues, and these two terms do not fall into the same category as mado "window" or miyako "capital city" whose kanji representations do not reflect their Yamato etymologies.
Thank you, Flaminius.