Add Price action returns 409 Version mismatch. Concurrent modification

[iznenad]

While testing the addPrice action with this data set in the mapper:
https://www.dropbox.com/s/jika9b7z5b722pu/Screenshot%202014-08-14%2001.22.36.png

A bunch of these errors occur:
https://www.dropbox.com/s/aczg6b4bkid9y29/Screenshot%202014-08-14%2001.21.50.png

I guess the problem is that a single product version gets updated simultaneously by 15 workers.
As the request is a post with a body which consists of an array of actions, it would probably be good to accumulate the actions before executing the request.

This doesn't seem trivial to me.
https://github.com/elasticio/sphereio-api/blob/add_price_nenad/extensions/addPrice.js#L7

It could be that my guess is wrong and the problem is something different.