How do we know what the possible surplus will be?
We take the Assessed Value and minus the starting bid. If the property is homestead, we then add 1/2 the assessed value.
We have been tracking surplus for many years and this method has proven reliable to show what the actual surplus is after the auction is complete.
When housing prices are high, the bids on these properties are also high and in turn this produces much more in surplus money than normal.
When housing prices are low, the bids hover around the assessed value and not much (if any) lower.
Of course, there are always exceptions to these rules.