Ahh yes autoflowers are notorious for not needing alot of feed espeically in the earlier stages of growth its a very tricky thing to get right. Best rule of thumb get the EC below 1 and only use extra nutrients if you see problems growing in soil she has an abundance of nutrients and impurities she can feed off adding more at this stage will result in overfeeding her. So yup your correct my friend flush this little lady for a few days and then re introduce a lower feed if you feel you need to. Hope this helps :) keep in mind also soil can hold nutrients much longer than other mediums :) Though it looks to me that your caluculations were only slightly off this is not a bad case of over feeding and will most likly not effect her in anyway. You will know a serious overfeed as the edges of the leaves would turn orange as a dwc grower its something I battle on a daily basis lol happy growing my friend :) 👍👊