Question 10, EOC, Implementation Shortfall. Page 58, Volume why, answering, question, problem

chandsingh

The question has 2 subquestions. I read through the answer but could not figure out why in question A, they use Bid price for benchmark while using mid-point for answering Question B.
My 2nd problem is how to realize that they are asking about $$$ or % when: “estimate the total implementation shortfall” .
I often do both for more prudence!
Anyone has the same concerns?
Thanks!