Custom Box Question

I am currently getting (50ct) custom boxes for
16" $37.5
14" $25
10" $12.5
customized, including delivery. Is everyone including delivery or just unit cost?

50 ct 3 color boxes:
14" 20.45
12" 17.99
It is shipped with our deliveries from Sofo foods. They warehouse for us from Star Box.

Since the custom boxes are considerably higher in price, here are some questions for you guys & gals:

     1) How often do you change the color or design of boxes. How easy is it and do you pay for setup or new plate fees?
     2) Have you tested different types of designs before deciding on the right one? or just went with the Logo and that's it? 
     3) Why did you choose your Color Scheme?  I ask because most seem to have 2 or 3 color choices due to costs.  Full color boxes I'm sure are too pricey for most or not worth the      extra cost.
    4) What's your opinion about Black boxes or Black background?  I see more and more samples of stores using black color which is interesting.  Do you think the colors would influence somehow the perception of the products quality or taste?  Or does it even matter?

1 - I have had my same design for approx 10yrs. You could change as often as you like but they will hit you with the plate charge approx $300
2 - Just pick a design you like and DO IT! If you are not using your logo with your info (phone number, website, order online @ …, WE DELIVER, ETC.) you are crazy
3 - cost will be more so we use red & black…approx 5 yrs ago we switched to a brown craft box. We are in a “green” marketplace so I think people appreciate that choice and our boxes stand out from the normal white ones in my market
4 - i know a guy tht swears black but I am not sold yet

Do have a number for him, I’ll called 6 times and no one has been able to help me nor return the call, thanks