I have never bothered not that I have filled the EQA yet but my A200 or even go back further my BMW 320 or X3.... I just purchased quality wiper fluid from an auto store or fuel station which then also get mixed in with whatever the dealer tops it up with during its service. I have just always made sure the solution chemical makeup is close to or matches what the dealer recommends no point paying a mark up just because it has the car brand on the bottle you will find it all comes from the same factory for most part.