Hi,
First please check whether you have stock in t-code /sapapo/rrp3, notice you check the correct location/product/planning version. You can also check the stock on hand in product master (/sapapo/mat1) on "lot size" tab.
In SNP planning book the key figure is updated by macro. So please first check whether the key figure is correct in standard SNP planning book 9ASNP94/SNP94(1). The key figure is filled by macro "stock balance" in standard SNP planning book.
Then you should check the macro in your own planning book.
BR, Ada