We notice that there is always a substantial difference between the WPT and LH speed index scores.
If I look at the Google LH documentation for Speed Index it refers to the WPT documentation suggesting that they have the same implementation.
If the technical implementations are slightly different and the scores were within a 5% interval I would think this is okay, but our testing is showing a huge difference. Normally at least 30% difference (WPT is almost always a lower score), but sometimes there is a difference of over 70% for the same test.
Is there a good explanation of the reason for the differences?