option to lower shipping after order is made?

Trying to figure best way to do this--any ideas would be helpful.

We have several products of different sizes, weights etc. Will be shipping in USPS flat rate boxes for the most part. Thing is, I have some small products that we could ship 10 of those items in one box. If we do flat rate it would add that amount for each of those items, correct? So someone ordering one of Product A would get charges $7 for shipping, and someone ordering 3 of product A would be charged $21 for shipping, even though we could ship it all in one box so we should only have to charge them $7 for shipping total.

Looking for a workaround for this --maybe one would be to be able to manually go in and change the shipping amount when we package their order so we know how much to charge them for shipping (usually lowering the shipping price).

Don't think we can really do it by weight because some products are light weight but bulky and would need to be packaged in a larger package.

And if they order a combination of items.... see where I'm going?

Any ideas?

Actually did some poking around and looks like Flat Rate would just charge $7 shipping no matter what or how many they order.

So I guess I need a solution that gives me more flexibility with shipping. Like they can order a bunch of Product A and we can ship in one box for $7. Or they can order one of Product B and we need a bigger box so shipping would be $12. But if they ordered Product B and a couple of Product A, we could ship in one bigger box and shipping would still just be $12. So looking for this type of solution.
Using Opencart 3.0.2.0

You can do this with Edit Order Line Items, and then refund whatever cost you charged that was extra. If you want to edit the Shipping line item with a higher price, though, you'd need some way to collect the additional payment. You could either call the customer to get their card info again, or use Collect Payment Later for that. It works well to collect additional payments (or full payments) after an order has been edited using Edit Order Line Items.

Feel free to take a look at the screenshots and demo site, and if you're interested let me know at www.getclearthinking.com/contact if you have any further questions.

Is there a way to set up shipping so if they order a particular quantity of a certain product, shipping price bumps up?
Like Product B...if they order 1 or 2, it's $7. If they order 3 or 4 of them, it's $14?

Not with Edit Order Line Items, but it sounds like you just want a better shipping calculation for your products. If you're using live USPS rates, you could use Hidden Shipping Adjustments Pro to adjust the price when a certain product is in the cart.

If you're not using live rates, then you could potentially use Category & Product-Based Shipping to set your shipping rates. That lets you set different rates for different products, so you could make the default shipping cost $7, and change that to $14 when certain products were in the cart.

Feel free to take a look at the screenshots and demo site, and if you're interested let me know at www.getclearthinking.com/contact if you have any further questions.

Thanks-- I will check that out! Are these two extensions able to work together? In other words, if we used that second one, would you be able to still go in after and adjust the shipping price (make it lower) after the fact? Not sure I'd need to but just wondering if that'd be a possibility.

Thanks again!

Yes, but you don't really need both, unless you want to adjust the cost of another shipping method (e.g. USPS) and still create your own rates separate from USPS. If you do want that, then you might consider getting Ultimate Shipping, which can do both those things. It can request rates through other shipping methods, so you can get rates from USPS and adjust them, as well as set up your own rates based on your own formulas.