BPV of CTD calculation and Principal invoice amount calculation

CFA Level III Derivatives
#1

Hi guys, I’m having difficulty understanding BPV of CTD calculation and Principal invoice amount calculation. I spent 3 hrs on it but couldn’t really figure out the difference and when those 2 formulas should be used.

  1. Principal invoice amount = (Futures settlement price/100) CFContract size
  2. BPV of CTD = Modified Duration of CTD1 bpsMarket value of CTD
    Is the Market value of CTD in the 2nd formula equivalent to Principal invoice amount in the formula 1?