How to access values from multi row EFF values in OM extension

Summary

How to access values from multi row EFF values in OM extension

Content

We have multi row EFF on sales order fulfillment line. We want to add validation on sales order fulfillment line. "Lot quantity" is a column in multi row EFF and validation should check the sum of lot quantity should be equal to ordered quantity at fulfillment line. We are planning to achieve this functionality using on save OM extension.

We can review/implement any other suggested approach.