Hi there,
I have multiple weight-based shipping rates on one of my stores - when an order contains different-weight products, the separate shipping rates for each product are added together… This is not wanted at all.
Is there any way to disable to adding together and just use the highest shipping rate for the weights? Or does anyone have any suitable workarounds for this.
Thanks 
Hi we are also having an issue with this. Our courier charges by weight but customers may add a few products of different weights to their cart. At the moment it is then adding all the shipping for each product rather than combining the weight for a total weight category shipping.
Hi there, we eventually got around this by implementing this app: https://apps.shopify.com/shipping-rates
Not overly cheap, but a good workaround as Shopify isn’t overly “friendly” towards NZ based shipping options, it’s more geared towards the US market. The app works well and the support team were very helpful.