Does anyone know the difference between the service factor "R" in the safety stock calculation and Service Level "Z" factor in the standard normal distribution for inventory planning? I've searched all the help and articles (and one of the articles is linked to many, many times). All they say is that R is a factor that is influenced by forecast accuracy and service level. The values are different than for the Z service level for example for 90% service, the normal Z value would be 1.28155. The R value SAP uses however is 1.6.
I'm trying to replicate a normal safety stock formula and I can't determine how the R is determined. Also, there is an exit WFCS_003 that allows you to define your own formula. However it appears that it might be for IS-Retail only. Does anyone know if this is the case?
Thank you for any insights.
Regards,
Paul Jackson