I've been trying to set-up product variants and tax overrides so as to achieve the following situation:
... with the aim that eBooks and Paperbacks are charged at different VAT rates in different countries.
I've set-up smart collections for "Book Tax" and "Digital Tax", so all "eBook" variants are members of "Digital Tax" and all "Paperback" and "Hardback" variants are members of "Book tax"
On the product page it states that it automatically appears in the "Book Tax" and "Digital Tax" collections.
When I go through the checkout process and use different countries for my address, I see varying tax rates but not the correct ones. When buying an eBook in the UK I get charged the Book Tax rate instead of the Digital Tax rate.
By removing and then recreating the tax overrides in different orders, it appears that the system logic is to look for overrides for the relevant country, and take the first override that applies to any collection of which any variant on the product is a member. If so, the implication is that you cannot use country tax overrides in combination with product variants. Can Shopify confirm this?
This is an interesting/frustrating problem. I think the concept for your solution is fine, but where you may be falling down is that collections contain products rather than variants. So effectively you're adding products (and therefore all variants within that product) to both tax collections. So it's only able to use one (the first?) tax override.
So your conclusion would be correct, you can't apply tax overrides at a variant level.
My solution would have to be to create separate products for digital versions of the book, and add those to a collection with the tax override for the new rules. Then create a product template that pulls in the digital product of the same book title when you're looking at the physical version of the product (if that makes sense?).
You'd need a method to link the versions of the book (same title? Same title + ' eBook'?). But that could be done.
Thanks for the reply -- that's exactly the same solution that we came to in fact, and it's not ideal but is a decent enough workaround.
We're a bit concerned that by going down that route we may be painting ourselves into a corner later on if the collections became version-specific and we then wanted to move the digital product back to being a variant of the product. That's bound to break something.
I'd argue that a digital edition isn't a variation of the same product, and I wouldn't advocate creating products where a digital version was simply a variant of a physical product. From experience there's a number of problems it could present, so I'd see this as a positive solution with better data integrity. That's my opinion, of course.
Glad to hear you've solved it though. Good luck with the site!