Do I need to check the Accounting date on the Stock valuation report?

In Stock, Period processing, Valuation, Stock valuation report, when running the report with the Accounting date box is checked and without the Accounting date checked, the results are different why?

The FUNSTVA report is used to print STK quantity, Unit price, and the Amount based on the costing method used. If more than one costing method is used on the products, it is possible to print the report using the "Primary issue method" costing mode so the report can be launched one time and apply the valuation method defined on the product-site for products with different valuation methods. Also, a specific valuation method such as Standard cost or FIFO cost can be selected if one valuation method is used on the products. 

When running the report for a specific Costing mode and not checking the Accounting date (ACCDATFLG), the report will use the data collected for stock transactions based on the date of the stock transaction (IPTDAT) in the stock journal (STOJOU) table.  

However, when the Accounting date (ACCDATFLG) is checked, only stock transactions that have been posted to the general ledger will be eligible for inclusion and the selected date is based primarily on the Accounting date (ACCDAT) value in the STOJOU table and not on the allocation date IPTDAT. Keep in mind that the stock transactions that have not been posted in accounting are not considered and if you want to consider all the stock transactions, you need to launch the stock accounting interface FUNSTKACC and the WIP posting FUNWIPACC.