to explain this , let me given a example:
to produce the powder, each pot machine produce about 60kg.
before we product another kind of power , we need spend 4 hours wash and dry the machine if a customer order 10 kind of powders and 1 case only (20kg). its would take us 40 hours on washing and dry the machine, ..so that's about 4-5 working day only produce 200kg powder.(normally should 600kg). 200kg which is not meet our economy order. syrup is more, 40case x 2.5kg per batch(per kind of syrup). each time if you order 4 case of it we need find other buyer sell 36 case of it.. (our cost increase too) so if our customer can always order a patch, he will always get better price.
*tip: all our product is pre-arrange production. so product is always fresh!