in context of a degree-progression, from what i know, all the intervals should be inverted/transposed to see whoever has the most valuable intervals in the whole progression. there are many things who contribute to making a central tone. not only if it has a fifth and a fourth, but in what order (the best case is where the tone is preceded by a fifth), who has the rhythmic accent (the first bar), which tone is the lowest in pitch in reality. after the central tone is established (which is hard sometimes) then all the chords reffer to this parent.
this means that if there's a F chord going to the C chord, and C is the central tone, then the F is the forth, even if in reality it comes before the C chord, or if it's in a lower octave (lower F to higher C is has the interval of a fifth, but it doesn't matter), it's still considered 4-1 from a degree-progression's point of view.
if F were the central tone, then it would be a 1 going to a fifth (1-5). the same notes on the staff.
hope i got it right.