New to ZC, UPS shipping module showing wrong number of boxes?

Hi, I have a new install of Zen Cart, everything seems to be working fine but for some reason when I test the shipping the number of boxes shown comes out wrong, and accordingly makes the shipping cost off.

My products are sold in groups of 4, so my Product Qty Minimum and Product Qty Units are both set to 4. Now when I go to check out the shipping calculator shows 3 boxes, however the weight is correct for 4. Weird :huh:

Any ideas? I have done quite a bit of searching but cant find anything else.

There are a few variables to consider... look first in your settings for
admin>>>configuration>>>shipping/packaging

Here is a screen capture of that page, thanks!

Heres a screenshot of whats actually happening as well, now the shipping price seems pretty close to me, but its weird that it shows 3 boxes:

Remember the boxes you PACK in are not the same "boxes" that the product is "contained" in...

If you have a situation where a minimum of 4 boxes (of product) must be purchased, each weighing, say 10lbs . That means that a single instance of "add to cart" is compelling the purchaser to a consignment of 40lbs (4 X 10).

Now... let's say that's all he orders for now... FOUR boxes of product at 40lbs total.

... But you only ship in CARTONS that have a total permitted weight of 20lbs per carton. (shipping/packaging settings).

... so you will need to PACK your FOUR boxes of product into TWO shipping cartons... (20lbs + 20lbs)

... see what I'm getting at?

Thank you for your reply!

I think I understand, but in this situation what confuses me is that I would think it would show 2 boxes, not 3. Very strange.

I guess my question is, where does it determine the per carton shipping weight?

Would it be the Maximum Package Weight?

Thanks!