I am trying to gather a time series data for Crude Oil Future prices (both Brent and WTI) to work on a project. I see that the BCOMCO (Brent) and BCOMCL (WTI) indices are constructed from the respective Futures prices with a rollover methodology.
I however, am failing to understand the difference between the various numbered indices (for example, the Brent Indices are: BCOMCO, BCOMCO1 (1 month forward), BCOMCO2 (2 month forward), BCOMCO3 (3 month forward), BCOMCO5 (5 month forward) and BCOMCO6 (6 month forward). The Security Description says for all the numbered indices says "composed of longer-dated futures contracts". What is the exact difference between these indices?