Hello!! Price Optimizer A / B modifies the price of variations? In my store each variation has its own sku.

Hello, Juan.
That's totally fine, because the application adds its own hidden variation to every single product in your store (it happens during Setup - that's why it's important to launch Setup from your app dashboard). This variation does all heavy lifting for price optimization. This variation is hidden for end-users, it is used and controlled by the application.
So, to summarize my answer: no, Price-Optimizer doesn't modify the price of variations, it adds one single hidden variation to every product in your store.
Hope it helps. In case if you have other questions - feel free to post a reply here or start a new topic.
Regards,
Dmitry.

Hi Dmitry, thanks for your quick reply.

My store is organized as follows: a product has multiple variations, each with its own sku, for example: the product with sku 00100 has 3 variations: 00100-01, 00100-02 and 00100-03, and each variation has your own price. The sku 00100 (that is, the main product, not the variations) has a price of 0, since it only works as a "grouper" of variations.

In this case, could Price Optimizer A / B work?

Hi Juan. I got your case. For now the application would work - but with discount from 0% to 5% (individually for each product). It's because at Setup it does 2 things:
1) Creates price variation for every product with 3 options of discount: 0%, 3%, 5%. That variation is controlled by Price-Optimizer to choose the best price possible.
2) Increases price of the product for 5% - that step would lead to nothing in your case because of zero prices. That's why as a result it would work - but with discount from 0% to 5%.
You could decide whether it's affordable or not for you to use the application in such state. I am going to fix this issue by replacing direct price modification with adding another price variation - it should make it working for your case too. But this enhancement will take time to implement: about a week I guess. I am going to keep you notified about any progress done regarding this topic.

Hi Juan, I have news. I've contacted to Ecwid-support to get an opportunity of checking the Ecwid behavior in described by you case: when the base price is zero and there is a variation with non-zero price. What I've discovered: price-modifiers are applied independently - so I just can't add my own percent-based price-modifier which will be applied on top of your value-based price-modifier of your variation.
So the final (to the moment) answer to this case is: no, it's not possible to make it working, because price-modifiers are applied independently and I can't modify the price by percent-based modifier over value-based modifier.
I am going to send an email to Ecwid-support about the order of applying price-modifiers. Maybe they shouldn't be totally independent and be applied one by one in that order that is defined by their order in user dashboard? I am not quite sure it could help - but why not, I think I should try at least) If you have any questions or suggestions - feel free to throw several lines here.