Why is Shopify double charging for ground shipping on my hair products?

[NorthAuthentic]

We carry hair products and only ship from one location. As some of our products are aerosol (can only ship ground), we created two shipping profiles.  One allowing only ground shipping ( aerosol cans) and the other for everything else (which includes the option for priority mail, Parcel select ground or UPS GROUND). 
If a customer purchases say a shampoo and a hairspray, even though these two products share a shipping method (ground) it is still charging them double shipping! I’ve seen customers charged $18 for two small products. This is making us lose customers as they are complaining that our shipping rates are too high! 
Shopify fix this! I’ve notified support about this and they just say, they’ll notify the developers that “I” have an issue with this. Seriously? What owner wouldn’t have an issue with losing customers we pay so much to get to our store. I’ve tried everything to fix this, but it is out of my hands and entirely in Shopify’s.  

[Anindita]

Hi @NorthAuthentic 

Unfortunately, this cannot be achieved with the inbuilt Shopify shipping as when using multiple shipping profiles, if orders contain products from different profiles or locations, this will result in combined rates at the checkout. Currently, the only available workaround would be to use an app like Multi Carrier Shipping Label App to set up more specific shipping rules.

Let me know if you have any queries, I will be happy to help!

[NorthAuthentic]

We shouldn’t have to install yet another app. This should be easily fixed by Shopify.

[HempPapí]

I agree, this is a fixable issue that we should not have to deal with on Shopify.  Your shipping profiles are quite useless if shipping per item is forced.  FIX THIS PLEASE SHOPIFY!

[Boxtherob]

Hey,

Has anyone figured out how to fix this problem yet?  I am having the same problem.