Why does my Measure only works on certain rows ?

Hello everone, 

I'm into my third week of using DAX in PowerBI and stumbled upon this hurdle where my measure only calculates certain rows but not all like what I would have hoped for. 

On the screenshow below, "Decline rate next 5 years_dynamic" and "Decline Rate Dynamic_S" are both measures I have created. 

"Decline Rate Dynamic_S" is just a score (1 to 5 score) that is assigned to the asset based on the magnitude of "Decline rate next 5 years_dynamic". My problem is that it assigns a score for most of the assets but left out some - see arrow picture below - and this just puzzles me. My intention is for it to assign scores for all the rows/assets. 

The code I have written for "Decline Rate Dynamic_S" is

Decline Rate Dynamic_S =
VAR Score1 = CALCULATE(SELECTEDVALUE('Score Tranches Input'[Decline Rate_SA]), 'Score Tranches Input'[Index] = 1)
VAR Score2 = CALCULATE(SELECTEDVALUE('Score Tranches Input'[Decline Rate_SA]), 'Score Tranches Input'[Index] = 2)
VAR Score3 = CALCULATE(SELECTEDVALUE('Score Tranches Input'[Decline Rate_SA]), 'Score Tranches Input'[Index] = 3)
VAR Score4 = CALCULATE(SELECTEDVALUE('Score Tranches Input'[Decline Rate_SA]), 'Score Tranches Input'[Index] = 4)
VAR Score5 = CALCULATE(SELECTEDVALUE('Score Tranches Input'[Decline Rate_SA]), 'Score Tranches Input'[Index] = 5)
RETURN
IF([Decline rate next 5 years_dynamic] <= Score1, 1,
IF([Decline rate next 5 years_dynamic] <= Score2 && [Decline rate next 5 years_dynamic] > Score1, 2,
IF([Decline rate next 5 years_dynamic] <= Score3 && [Decline rate next 5 years_dynamic] > Score2, 3,
IF([Decline rate next 5 years_dynamic] <= Score4 && [Decline rate next 5 years_dynamic] > Score3, 4,
IF([Decline rate next 5 years_dynamic] > Score5, 5)))))

Any help on this would be very much appreciated.