4. During the 1st round. 84 - (6+5+4+3+2+1) = 63 remaining in the draw deck
5. At the final moment of the 1st round, the last remaining bidder will draw 1 card from the deck and place it into the market. So, 63 - 1 = 62 remaining in the draw deck at the beginning of the second round.
You just double counted the last player. The 1 in step 4 is the card for the last remaining bidder that goes into the market.
Round 2 begins with 63 cards.