You're an engineer and not a dollars and sense/cents guy but in case otherwise, I will ask ...
Why is there a focus on the effective rate?
With a fixed contract a rate is agreed upon. The volume is used based upon projections. Using the multiplication table, a total revenue is calculated and paid in installments.
How can, for example, an LG argue that the rate should be lowered based upon what turned out to be the effective rate? The effective rate is not the rate initially agreed upon. They initially agreed upon an actual rate and because they "knocked it out of the park" the effective rate came out lower compared to the actual rate (ie. the positives for a manufacturer to sign a fixed agreeement if your bat is corked).
The disputes appear to be between what the cost was and these companies want to maintain it, IDCC thinks otheriwse and want to focus on the actual rate agreed upon in the fixed agreement.
Effective rates are like snowflakes, no two are alike. The effective rate is going to be different for everyone with a fixed contract. But the actual rate, agreed in the contracts, could/should be all the same.
P.S. Wedding was good. Music was fun. Nothing like leaving a wedding and having the question "Where are they now?" answered by "They do weddings?!"