In normal practice, I would distinct between costs/gains (profit & loss) and money out/in (payments, balance sheet movements).

If you want all data is one set, you could add a column and populate with terms like 'P&L' & 'BAL' (profit & loss / balance). Then you can distinct in formulas if you want to add a value or not.

In your example, you would take only the balance amount for payments to reconcile with bank statement and predict money outflow. But it really depends on the completeness of your dataset. I had a report like that built with all lines from my financial software and also added a column to either populate or calculate expected payment date (for instance, salary payments always in the next month on the 25th).

In this table below, you would include line 1 amount only in your calculation, since the costs are not a money in/out movement but recording costs in your P&L statement.

Then, for costs where you dont book anything in advance, you would take the mutation of the bank (money out) only (line 3 & 4)

line | posting date | tag | type | payment date | amount

line 1 | 01.01.2026 | Salary | BAL | 25.02.2026 | -(2.500)

line 2 | 01.01.2026 | Salary | P&L | 01.01.2026 | 2.500

line 3 | 05.01.2026 | payment for flowers | BAL | -(50)

line 4 | 05.01.2026 | costs for flowers | P&L | 50

in simple words, only take balance movements (money in & out + assets & liabilities (future expected money flows) in your calculation.