I put liability, but really it's a combination of both. As I stated in the other thread, I had employee stock options that I knew would take a huge tax hit that couldn't be deferred for too many years, so I discounted the value by the taxes I would pay. It just didn't make sense to me to look at, for example, $1M as $1M when I was only going to get about $600K. Modeling a $400K one time expense didn't really make sense to me, especially when trying to figure out when I had enough to retire.
Once I did that, I realized my 401K and IRA would also take a tax hit at some point, so I discounted that by an estimated tax rate of whatever I think I'll be paying when I pull that. I know some will say I can't know what rate that will be, but isn't that just as true if I was trying to estimate that as an expense? And I know some of you will be paying virtually no income tax in retirement, but that's not my case. I further discount my taxable account by discounting the unrealized capital gains.
I do have an expense item budgeted for dividends I get on my investments, which are fairly consistent. It never occurred to me to try to discount my stocks by dividends, as you asked in the other thread.
Accountant-type people may shudder at my method and inconsistency, but I don't care, unless you show me a significant flaw with my system. Telling me I have to treat it as an expense is not going to fly by itself.