get_history_bill issue

In get_history_bill, 小单净流入+中单净流入 = ABS(大单净流入+超大单净流入), which leads to 小单净流入+中单净流入+大单净流入+超大单净流入 = 0 . Something must be wrong.

Thanks.

Start by locating the get_history_bill entry point and trace how the four net-inflow values are obtained and combined. Compare the reported relationship with the source data and determine the intended invariant. Done means the calculation no longer produces the inconsistency described in the issue and the behavior is verified with a representative result.

Written by the indexing model from the issue text.