The wording is very weird ("Free Mix only is 0.001 BTC only to") and I don't really know what I should do. It says the min is 0.005 BTC, but the Free Mix is only 0.001 (?). So, I can actually send 0.001 BTC? What if I send more (e.g: the entire 0.0013 BTC)?
It has been discussed there on Jambler's official chat group, the answer is below from the Jambler admin. So the same goes for all Jambler partner mixers who are using their default script.
It does have to be exactly 0.001 BTC, because this very amount is what communicates your intent to use trial mixing to the system. Think about it, there is no other way for the platform to know if you want trial or regular mixing. So, any other amount will be treated as regular mixing, and the usual commission will be charged.