I would like to know if someone has some experience with the level of detail the letters from manufactures need to be made. Specialle regarding the source of recycled content.

For example we have a letter that states the following information regarding post and pre consumer recycled content:

Post-consumer scrap accounts for approximately 25.6%, while pre-consumer scrap accounts for approximately 6.8%

My question here are the following:

Will this information will be sufficient to comply with credit's reviewers?

Does the letter need to state where the post/pre consumer recycled content come from?

Is it necesary that the letter be for an individual project, or a generic letter will be enough (like a letter saying all of our xxx products have xx% of pre/post recycled content).

We really appreciate anyone's help.