past perfect ?

hello

I would like to know why in this text past perfect is used for first two verbs cause the sequence of time is respected

here is the text
This time Tony and I had become the Producers, but more importantly we had written six songs, each to make up a soundtrack to go with the show . We called in independant theatre Patric Hanson to assemble a professional cast.

The sequence of time is
first become a producer
Then wrote some songs
called

or

first became producer
then wrote
called

anyway first 2 events took place before the last one and it is pretty clear , to my opinion past perfect is not needed
So why past perfect ?

In this text I have found another exemple of past perfect I dont understand

This date was constantly re scheduled to accomodate everyone for rehearsals which had now been set for march 88.
Past perfect + now first time I have seen that

THANK YOU FOR YOUR ANSWER