Hello!

What he needs is Experimental Vials Protections and the one that is obtainable from Great Plates is Advance Experimental Protections. Aside from that, spending 3600 in that event isn't that much efficient much especially if people want to maximize the value of their coupons for more gain since it will only trigger the first few milestones of Fukurokumaru's Deal if it is open at the same time with Great Plates. It only worked for you so far since you have a specific and target from that event but it will not work for other people who have a different set of goals.