Sales order SSD not aligned to common Date for Shipset entered manually

Hi ,

we have situation where user entered the shipset manually while entering the order manually. per expectation , all lines to have one common SSD based on max lead time. however , each line is having SSD based on lead times. whenever new line is added with Ship set or user un-assigns and assigns the ship set back then only all lines gets SSD aligned.

so is this bug or expected behavior by oracle , if customer master - Ship to is not enabled with Ship Set but user assigns ship set manually??

let me know your experience and possible solution for this issue.