Hi Somin, I'm sorry to hear this, It will give you allot of headache with this massive goupbuy.
Of the mirrors for red and green are perfect, isn't it a idea to ship the mirrors for everyone who will use them with red and green.
I think less than 20% of all the mirrors in this groupbuy will be used for blue, as blue diodes are 8x as powerfull as red diodes.
If the Company who made the mistake supply you with lets say 150 mirrors (25% of the order) suitable for 445nm, and supply us afterwards with those mirrors, I think we all are happy.
Just an idea.
I rather have 2 different mirrors with R>99% than a broadband mirror with 97% reflection