What is difference between /SAPAPO/PEG1 and /SAPAPO/RRP3..?

Hi Everyone,

I want to know difference between /sapapo/peg1 and /sapapo/rrp3,

1 - If we create order by peg1 and rrp3 both will be same..?

2 - If both are same why SAP provided peg1 for order creation

Thanks and regards

Narwdeshwar