Yeah most stuff (aside from FFA and rot and some 0's) has always been entered into the DKP system... it's been kept extremely accurate over the years by tedious careful attention. FFA and 0 bid stuff does not qualify as a sale, thus does not have to be entered, it's loot officer's choice on entering those as far as I see it. This does NOT mean our system hasn't been kept accurate because we didn't enter rot loot, etc... it technically is not a sale involved in our economy and doesn't matter whatsoever.
As long as an item gets bid on, it's definately going to get entered into DKP and become part of that item's history. If the item ends up going for 0, FFA, rot, whatever... it's no longer necessary to enter that value into the same equation as above. You have all the history you need prior to it getting played out. So still I feel it's loot officer's choice whether to make those entries or not.
Btw our DKP system doesn't need much "improvement"... it's been kept working well for quite a long time... most small changes we make are for management reasons but also a rare change occasionally to keep bidding in line with content and our numbers. Most guilds do this from time to time... it is nothing out of the ordinary... so relax.