Indexes

Can someone tell me what advantage you receive by using indexes for I18 using hi lo versus just playing basic strategy. Also, does the advantage change for each situation or is the advantage for each situation pretty close to the same. For example, does using the index for 16 vs 10 increase your advantage more than using the index for 15 vs 10 or any other situation or are they all about the same. I am interested in the following games if anyone has this info. SD, DD and 6-deck all with the following rules. H17, DAS, DA2.