Nah that info is based on the original strain. For delta we simply don't know, there's not been enough research done, the strain is still relatively new.
The reason why it makes sense to get your second AZ early is that delta is at risk of running rampant soon.
If you get the second early its efficacy might fade quicker, but that doesn't matter so much if we get boosters next year. The important thing is surviving this year.