Sure there could be a general field rather than a tax specific field, the field would account for estimated expenses and it would reduce the payout amount in order to attempt to measure net pay as compared to gross pay, yet from my current thinking that kind of extra field seems to have tendencies to overly complicate the tool.  What do you think bitmover?  Do you want to add an expenses field?

One of the main reasons to use this kind of a tool is to get some kind of idea regarding how much BTC to withdraw and to even show maximum withdrawal amounts based on current BTC price conditions in relation to the 200-week moving average, and surely there could be some cases in which the actual benefits of the coins is reduced due to various transaction fees, taxes or other costs that could be applied right at the time of withdrawal, yet something like taxes might be a matter of how it is categorized within reporting categories that might be somewhat ambiguous and difficult to capture even if we were to put a general expenses field in there, and even if such an "expenses" field might be helpful, I am still leaning towards thinking that such a field adds more clutter, complication and distraction to the idea than it benefits - even though it is not totally irrational to want to include the consideration of those kinds of personalization ideas.