I’m fairly new in dealing with board fabrication topics and Need help figuring out attrition quantities requested by vendor.

We recently changed vendors due to LT, quality issues, and better pricing. We had already procured the quantities needed to complete boards with a 10% attrition. However, new vendor is requiring large quantities to account for lead attrition; i.e. for 90 parts resistors needed, extra 150 for parts for lead 5% attrition.

Distributor’s LT and stock is too long and too low to buy the quantities requested.

Dow you know why so many are required? What should I expect from vendor when discussing issue?

How can we overcome the problem? What can I propose?

Can leads be added? At what cost?

Thank you in advance for the advice.