An article on twitter explained the following
It was in the best interests for GWS to actually trade out of the top 10 for draft picks of similar points value. The reason being is that if their Academy prospects get nominated around the mark of 7 or 8 as expected, being top 10 GWS gets a 20% points reduction to counter a bid on them. However if they drafted them with the pick 7 or 8 they had, it would have cost them more points paying the standard rate.
It also explained that if their academy prospects are nominated slightly higher, it can possibly push them slightly into deficit for 2016, so they would likely need to trade for more picks to get their players.
I think it potentially means that by trading themselves out of the top 10 and having pick 10 as their first pick, they are likely to still be able to get 3 top 10 quality picks. They are listed as having 12 draft picks going into the draft, but a lot of those later picks are purely for points to bid on their academy players.
EDIT: This article goes into depth a bit more. Hawthorn boss wants an investigation
www.heraldsun.com.au/sport/afl/hawthorn-...308a654d43d0261b4361