The stock EI routine, as you have listed is just a starting point. EI in general assumes a 50% minimum water change per week, and adequate CO2
The idea is that even if you have zero nutrient uptake, you will never have an excess build up.
The +/- means adjust as needed based on the results you get. The dangers (algae, plant health, etc.) tend to come from running out of a nutrient. So you can start with EI as listed, then after say a month, adjust up or down based how your tank is doing.
BTW, the 1/8 (10ml) trace, is either 1/8 tsp dry CSM+B, or 10ml (2tsp) of liquid Trace mix.