Material availability lead time in SAP

Dear SAP GUrus,

I would need your help to validate what are the fields in SAP which influences Material availability lead time in SAP. Please confirm if lead time depends on Availability check (MRP 3), or ABC indicator (MRP1) or any other field maintained in SAP. My understanding is lead time calculation in SAP is only dependent on Procurement type (E, F or X) maintained in MRP 2 tab. I will exclude X for sake of simplicity.

I am being trained in calculating material availability lead time as following. Please help me to understand if it is correct or not. If not could you please help with relevant logic to calculate lead time?

If Procurement type (MRP 2) is F

Material availability lead time = Planned delivery Time (MRP 2) + GR processing time (MRP 2)

IF procurement Type (MRP 2) is E

IF Total replenishment lead time (MRP 3) is 0, Material availability lead time = GR processing Time

If Total Replenishment lead time (MRP 3) is >0, Material availability lead time = Total replenishment lead time

Thanks in Advance for your help

Best Regards

Rahul Gupta