Forecast price calculation flow 

https://app.diagrams.net/#G1GuqjSLqoK1zjw2jr4DRt07uxWzGFZEK6

Glossary 

Term Definition 
SAP active price the Net price in the forecast query (\Measures\Net price ) for which the value component key is 2. In case 2 is not available, the value component key equal to 15 will be considered (it happens only in the case of GBU=TS)  
Last SAP active pricethe last  ''SAP active price'' reported in the forecast query per CPC 
HL projected forecast priceThe 
Forecast price