Calculating Treasury Futures - CTD vs Futures Price

I know the formula is this:

(D T_−_D I) P I D * ConversionfactorfortheCTDbond


For the Price of the cheapest to deliver, if they give you futures price and CTD Price, we should use CTD instead? Example 11 in Reading 19 calls it the “futures price” in the example but states the formula as above, but wasnt sure what to do if we get both, because it’s a bit unclear to me how they differ.